Answer:
d. Hello Dr. Smith, I have a question about my grades.
Step-by-step explanation:
Sarah is in a position of authority, so first Jerome has to greet her by her title and surname, so Dr. Smith.
Then, when going about his grade, he has to be careful. Just asking about the grade, as is done in the a. option, is a bit gross, that is, very direct.
So the correct answer is:
d. Hello Dr. Smith, I have a question about my grades.