Which Observation Best Illustrates the Conclusion That the Norm of Reciprocity

Which observation best illustrates the conclusion that the norm of reciprocity can influence helping behavior?

A) If someone has the opportunity to help you but chooses not to,you are less likely to offer them assistance when they need it in the future.
B) Individuals are more likely to offer assistance to others who are perceived to be "deserving" of help.
C) When people are in a situation in which they feel that they have received more benefits than they really have earned,they are eager to help those who are under benefited.
D) Instead of helping others out of concern for their well-being,sometimes we offer assistance simply to avoid looking bad.