A cost that has already been incurred and cannot be altered by any present or future managerial decision is called a:

Explanation

Core Concept: Sunk Costs are past, unrecoverable outlays. Because they cannot be changed by future decisions, they must be ignored in prospective decision analysis. Context/Distractors: Opportunity cost is the value of the next best alternative given up. Marginal cost is the incremental cost of producing one additional unit. Exam Tip/Key Fact: Classic example of sunk cost: money spent on past research and development.