A Fundamental Problem Inherent in Any Intertemporal Trade Is That

A fundamental problem inherent in any intertemporal trade is that:

A) one party to the agreement has an incentive to accept a payment or good now and then not deliver on the future obligation.
B) one party to the agreement may know more about the future than the other.
C) the party obligated to make the future payment becomes less motivated to ensure that the obligation will be met after receiving the initial payment.
D) All of the above.
E) None of the above.