Which One of the Following Statements Is Not Correct

Which one of the following statements is not correct?

A) Opportunity costs are only considered when resources are limited.
B) Short term decision making is all about analysing those costs that will change as a result of taking a particular course of action.
C) Contribution analysis is used to determine how many units of a product or service a business has to sell in order to cover all the costs of the business.
D) Both fixed and variable costs influence future short term decision making.