Costs that are always relevant in decision-making are:

A) avoidable costs.
B) future costs.
C) fixed costs.
D) sunk costs.

Avoidable Costs

Avoidable Costs are expenses that can be eliminated if a particular decision is made, such as discontinuing a product or service.

Future Costs

Expenses or expenditures that are expected to be incurred in future accounting periods.

Fixed Costs

Regular, constant expenses that a business incurs regardless of the level of goods or services produced.