Why Might a Member of Congress Engage in Casework

Why might a member of Congress engage in casework?

A) Casework is often mutually beneficial for the member of Congress and his or her state or district.
B) Casework guarantees re-election and a higher salary for the next congressional term.
C) Casework provides direct benefits to the member of Congress, even if the casework is ineffective.
D) Casework ensures that a member of Congress gets placed on a committee in Washington.