I am beginning my second year and have passed my qualifiers. We are required to take an entire sequence of probability theory which spans two semesters. This class is killing me. I am anticipating that I will not be able to solve a single question on the midterm, the homeworks are impossibly hard - this is the first year they offered this course. My entire cohort feels more or less this way about the difficulty of this class. I've had a 4.0 since my masters up to my first year here. I suspect due to all the time I am sinking in this class, and the fact that I am barely learning anything, that this 4.0 will no longer be there after this year/semester.
But I am a PhD candidate at this point, and there are no qualifiers or other department mandated exams on this material. In any other department, I am supposed to be spending time doing research or at least looking for topics and potential advisors. I am turning to you guys to ask - what should I do?
A. stop worrying about GPA and focus on developing a research direction and the other easier classes
B. grind for the A - a good grade in this class will be impressive for advisors