To Assure a Well-Defined Solution to the Consumers' Intertemporal Choice

To assure a well-defined solution to the consumers' intertemporal choice problems,we must assume that consumers' preferences exhibit the properties that

A) consumers are all identical and that more is always preferred to less.
B) more is preferred to less and that consumers prefer diversity.
C) consumers like diversity and that more is sometimes preferred to less.
D) more is sometimes preferred to less and that first-period consumption and second-period consumption are both normal goods.