Opportunity cost is

A) that which we forgo, or give up, when we make a choice or a decision.
B) a cost that cannot be avoided, regardless of what is done in the future.
C) the additional cost of producing an additional unit of output.
D) the additional cost of buying an additional unit of a product.

Opportunity Cost

The cost of foregoing the next most desirable choice when a decision is made.

Out-of-pocket Cost

Direct payments made by individuals for goods or services, not reimbursed by insurance or other means.

Marginal Cost

Marginal Cost is the cost incurred by producing one more unit of a product or service.