Which of the following statements is correct?

a. The demand for future goods is derived from consumers’ utility maximization problems over current and future consumption goods

b. It is the present value of future consumption goods that enters into the budget constraint of a consumer’s utility maximization problem over current and future consumption goods

c. The solution to a consumer’s utility maximization problem over current and future consumption goods can be interpreted as wealth not currently consumed that is invested to yield future consumption

d. All of the above.