Stavros and Craig Have Been Friends and Roommates for Many

Stavros and Craig have been friends and roommates for many years. Lately, Stavros has been feeling dissatisfied in the relationship. He notices that Craig discusses his personal problems, but he never seems to have time to listen to Stavros's problems. Craig has a tendency not to clean up after himself, and he's quick to borrow "a few bucks", but never seems to repay the money. According to equity theory, Stavros is feeling dissatisfied in the relationship because he is

A) over-benefitted.
B) over-looked.
C) under-looked.
D) under-benefitted.