According to Elaine Hatfield and Richard Rapson (1993),why Is an Exchange

According to Elaine Hatfield and Richard Rapson (1993) ,why is an exchange approach more common in casual relationships than in long-term relationships?

A) In long-term relationships, it's hard to assign values to resources.
B) Equity issues become less important in long-term relationships.
C) As people age, they become more concerned with communal values.
D) Emotion plays a greater role in casual relationships.
E) In long-term relationships, it becomes difficult to keep track of all the monetary investments.