Which is the best example of the use of legislative oversight by congress?

Question

the answer choices are between the following  A. The Supreme Court ruling an act of Congress is unconstitutional B. A memeber of the F.B.I appears before a congressional committee C. Congress votes to approve declaration of war C. A presidential veto of a congressional bill

Answer 1

B. A member of the FBI appearing before a congressional committee.

The first answer choice has to do with judicial checks and balances on the legislature. The third answer is a legislative action that is in line with separation of powers. The fourth answer has to do with checks and balances.