Fritz is taking an examination that consists of two parts, A and B, with the following instructions:
Part A contains three questions, and a student must answer two.
Part B contains four questions, and a student must answer two.
Part A must be completed before starting Part B.
In how many ways can the test be completed?
(A) 12
(B) 15
(C) 36
(D) 72
(E) 90