The leader of a federal political party made the following campaign promise: "my administration will increase national defense without requiring sacrifices elsewhere in the economy." the promise can be kept if:________
a. the economy moves along the production possibilities in the direction of a greater quantity of defense.
b. the economy moves from a point inside the production possibilities curve toward a point on the production possibilities curve.
c. the production possibilities frontier shifts outward due to an improvement in technology.
d. either b) or c) occurs, but not as a result of a).