Which of the Following Statements Is True

Multiple Choice

Which of the following statements is true?

A) In real life, the curvilinear nature of variable costs is questionable.
B) In real life, fixed costs are fixed in total and do not change at various activity levels.
C) Within the relevant range, there is rarely a straight-line relationship for both variable and fixed costs.
D) Within the relevant range the linear assumption is valid and useful for cost behaviour analysis.