That’s NYU’s official policy on standardized tests. It applies to Stern as well.
So if you’re submitting the SAT I results, you are not required to take the subject tests. But usually the more competitive applicants will have a few subject tests. Pretty much everyone takes Math II. If you want to take a second or third, just choose the subjects you are strongest in. It doesn’t have to be a humanities test.
You are not required to submit AP Exam scores or regents exams scores. My school lists our regents scores on our transcripts so NYU did see my scores.
I personally only submitted one SAT I score and 3 AP exam scores and didn’t take or submit any subject tests.