Which of the following costs are always irrelevant in decision making?

A) avoidable costs
B) sunk costs
C) opportunity costs
D) fixed costs

Sunk Costs

are past expenses that have already been incurred and cannot be recovered or changed, and thus should not affect future business decisions.

Avoidable Costs

Expenses that can be eliminated if a particular decision is made, not incurred in the absence of the decision.

Fixed Costs

Fixed costs are those expenses that do not change in total despite changes in the volume of goods or services produced or sold.