I believe it is B.) 177? I had to do a bit of reading for this one. Turns out I didn't know how to solve this one.
This may help you: Euclidean algorithm - AoPSWiki
(you may want to see the second link first)
I just wanted to say that I don't think these are math level 2 problems. They wouldn't be so hard, in my opinion. I did some online searching and confirmed that these problems are AIME problems. Kudos to your tutor for challenging you! The solution is also online most of the times so you can usually google search for it. See this: 2000 AIME I Problems/Problem 12 - AoPSWiki