When something is produced there is always.
a. a buyer.
b. an opportunity cost.
c. an elastic supply.
d. a profit.

The answer is B.

When something is produced, there is always an opportunity cost .

Opportunity cost is described as the loss of potential gain from other alternatives when one alternative is chosen. For example when we decided to produce a product painted in yellow over green because we think yellow will be more popular. Even if we're correct, we're still missing the potential gain from the one who likes the green one out there