The phrase gains from trade refers to the:

A) profits obtained from sales of a good or service.
B) increase in total output that is realized when individuals specialize in particular tasks and trade with each other.
C) gains that one obtains by taking advantage of an uninformed buyer and selling at a higher than average price.
D) gains that one obtains by taking advantage of a temporary discount,or sale price.

Gains from trade refer to the increased output, efficiency, and welfare that result from specialization and trade. When individuals or countries specialize in tasks they have a comparative advantage in, they can produce more efficiently, leading to an overall increase in total output. By trading with others, they can obtain goods and services they don't produce themselves, allowing for a higher standard of living. Gains from trade benefit both parties involved, and the overall economy as a whole. A, C, and D do not accurately describe gains from trade.