According to economists, gift registries, returning gifts for cash refunds, and "recycling gifts":

A. are inefficient because the time spent in these activities is never worth the benefit
recipients receive from doing them.
B. are equally efficient because the recipient gets exactly what he wants.
C. are more efficient than if givers simply gave cash gifts.
D. increase the efficiency of gift-giving because they allow the recipient to consume goods
that provide greater utility and transfer away those goods that are less satisfying.

Answer: D