The Leader of a Federal Political Party Made the Following

The leader of a federal political party made the following campaign promise: "My administration will increase national defence without requiring sacrifices elsewhere in the economy." Under what circumstance can the promise be kept?

A) if the production possibilities frontier shifts outward due to an improvement in technology
B) if the economy moves from a point on the production possibilities curve toward a point inside the production possibilities curve
C) if the production possibilities curve shifts inward due to better education and worker training
D) if the economy moves along the production possibilities in the direction of a greater quantity of defence