The productivity gains achieved by specialization are due to A. comparative advantage. B. lower opportunity costs from switching production from one good to another. C. scarcity. D. absolute advantage.

The correct answer is letter "A": comparative advantage.

Explanation:

Comparative Advantage is an individual, business, or country's ability to produce a good or service at a lower cost of opportunity than its competitor. Getting a comparative advantage does not mean that one organization is completely better at producing a good or a service than another. It implies that it sacrifices less to do so. Comparative advantage allows firms to specialize in the manufacturing of the goods or services being produced at a lower cost.