Assume That a and B Are Both Priced at $1

Multiple Choice

Assume that A and B are both priced at $1 per unit and that Mary has $10 to spend on A and B. She buys 6 units of A and 4 units of B. The marginal utility of the final unit of A bought is 12, and that of B is 8. This indicates that

A) Mary's consumption is in equilibrium.
B) given another dollar, Mary should buy an additional unit of B.
C) to maximize utility, Mary should buy more of B and less of A.
D) to maximize utility, Mary should buy more of A and less of B.