If a Consumer Is Choosing the Optimal Combinations of Two

Multiple Choice

If a consumer is choosing the optimal combinations of two goods X and Y, and then the price of good Y decreases, this causes:

A) MU/P of good X to increase, so the consumer now must buy more X to find a new optimal combination.
B) demand for good X to increase.
C) MU/P of good Y to increase, so the consumer now must buy more Y to find a new optimal combination.
D) MU/P of good Y to decrease, so the consumer now must buy more Y to find a new optimal combination.
E) the demand for good X and good Y will not change.