Cost-Volume-Profit Analysis Includes Some Inherent,simplifying Assumptions

Multiple Choice

Cost-volume-profit analysis includes some inherent,simplifying assumptions.Which of the following is not one of these assumptions?

A) Cost and revenues are predictable and are linear over the relevant range.
B) Variable costs fluctuate proportionally.
C) Changes in beginning and ending inventory levels are insignificant in amount.
D) Sales mix will change as fixed costs increase beyond the relevant range.