C. The question is simple enough to answer without applying algebra.
During one part of a interview for a quantitative finance job, my S had to solve a difficult math problem while loud music played and someone tried to talk to him. The guy literally stood over him talking the whole time. S said the most distracting part was thinking about how ridiculous the situation.
But realistic depending on the work situation. Many places quants can work can be noisy and disruptive.
My daughter had another phone interview today with a different company. She called me to say it was a "normal"interview (comparing it to the one where she got asked the bat and ball question). I think having an odd interview, can be off putting to the candidate.
Now another company is having her take an on-line SQL assessment test. They really make you work for a job today.
Fun process isn’t it? D did all this in the spring, a bunch in a row, several progressed to fly-in interviews in the same month. It was like a side job, doing all the assessments and phone interviews and coding assignments, nevermind the actual in person interviews - she missed her senior awards night and won an award, too 
Well, she is trying to do this while she has a full-time job. Two weeks ago she had a research PowerPoint to do for a job interview (they said to spend 3-4 hours on it). Funny to have to do this when she already has a proven work record of accomplishments.
A long time ago, DH applied for a job at a local engineering company. They asked for a LOT of stuff from him, including many pages of design calculations. It was a big task. I seem to recall even having to FedEx some stuff up from Texas. After all that, the company didn’t get back to him. When he inquired, they said, “Oh, we decided not to hire anyone, after all.” Grr.
I wonder if the applicants were actually doing work the firm needed to complete. I bet you can save a lot in payroll that way.
oooh, I’d like to know what some of the questions were. I’ve been giving them out to interviewees for years. But mine are never canned or super tricky questions - they are always real life problems, of which some of the questions actually need to be solved by myself or someone in my group lol.
This may be more job relevant if knowledge of SQL is necessary on the job (compared to the bat and ball). But then it also speaks to the tendency of employers trying to select for the perfect match now, rather than for ability to adapt to future changes (admittedly not the easiest thing to test for).
From a job applicant point of view, the job market is probably more like a recession than a low unemployment time, given how selective employers are.
You can do a web search for “SQL interview questions” to check whether the ones you give are common “test prep” examples that may cause you to overrate those who did “test prep” relative to their general SQL skills.
My guess is these are well paid positions?
In my line of work, investment analysts had to prepare a full credit analysis and present it to a full board room of people. It would take much more than 3-4 hours I’m sure and I have no doubt it was at least a tad intimidating.
However, it is a commitment with costs and legal issue to bring an employee onboard. A bad fit can be costly in many ways so avoiding a bad hiring decision is important.
I don’t think it is the level of the job, so much as the type of company - smallish tech companies. I think the SQL assessment is something she does online and the company probably purchased to use.
It is fairly common for computer companies to start with a phone interview or web quiz (both typically ~1 hour or less) to test basic knowledge (as the employer sees it) before moving the applicant on to the on-site interview (which is more expensive, in that it may involve multiple employees each taking an hour, plus travel costs for a non-local applicant).
But it can be annoying to the applicant when the company wants to do multiple of these to decide whether to move on to the on-site interview, or if it is slow enough that it can be over a month before an applicant who passes moves on the on-site interview. Seems like the employers are in no hurry, perhaps believing (probably correctly) that even good applicants will not be picked off by other employers that quickly. It was not like it in the past, when employers that slow usually fulfilled the “you snooze you lose” saying.
I used to work as a chemist for a major pharma company. During our interview process, one senior chemist used to throw a God-awful structure on the white board and ask the candidate how he/she would synthesize it. Thing was, that compound was something we’d been trying to make for months and couldn’t. Sure, we were always looking for new ideas - but I think the interviewer was just being a jack***.
Not saying you’re a jack***, Professor Plum! But this guy was…
I usually move on to the next employer when they start doing those kind of evaluations. They’re trying to weed you out by doing a half-baked IQ test. I call it a red flag. It means there’s idiots in high places. As a grown adult, I expect questions to be relevant to the job and my qualifications.
When I interviewed candidates for entry level jobs (law firm, investment bank) half the interview was about, “would I enjoy working with this person?” The questions were generally pretty open ended and related to the applicants’ interests as presented on their resume and their ambitions. My theory was if they could not engage me in something they are interested in, it was unlikely that they would fit well in a team, which is important in those professions (at least what my group was doing which was transactional). The second half was about trying to assess brainpower. I did not use any of these “puzzles”, but relied on questions involving their schoolwork. For non entry level jobs, a lot more attention was focused on past experience, including the why’s of why they were looking to change jobs.
The answer would be different if you grew up in Chapel Hill, NC. 
Many of the true reasons someone wants to change job will not be told during an interview, because they involve disclosing conflict between the applicant and other employees, which typical interview coaching says never to reveal.