Assume a consumer purchases a combination of goods X and Y such that MUx / -Px = 20 units of utility per dollar and MUy / Py = 10 units of utility per dollar. To maximize utility, the consumers should buy:
A) neither X nor Y.
B) less of both X and Y.
C) more of both X and Y.
D) more of X and less of Y.
E) less of X and more of Y.