We assume that the representative consumer's preferences exhibit the properties that
A.
they are convex and that more is always preferred to less.
B.
more is always preferred to less and that each consumer has one strictly favorite period of time for consumption.
C.
each consumer has one strictly favorite period of time for consumption and that current and future consumption are both normal goods.
D.
current and future consumption are both normal goods and that the consumer likes diversity in his or her consumption bundle.