Refer to the Accompanying Figure

Refer to the accompanying figure. If this economy were currently operating at point D, then in order to make more movies:

A) the first productive resources to switch to making movies should be those with the lowest opportunity cost of making milk.
B) the first productive resources to switch to making movies should be those with the highest opportunity cost of making milk.
C) no productive resources would need to switch from making milk to movies because point D is already efficient.
D) no productive resources would need to switch from making milk to movies because each resource should continue to be used according to its comparative advantage.