Answer:
b. A cost that differs across decision alternatives.
Explanation:
When managers make business decisions, some costs are incurred when such decisions are made. They are called relevant cost. The main purpose of relevant cost is to avoid duplication of data that are not necessary, which could further make business decisions complicated.
Example of relevant cost is when a business or an organization checks whether or not to sell a business unit. The cost incurred in such decision is called relevant cost.