Which of the Following Is Not an Underlying Assumption of a Conventional

Which of the following is not an underlying assumption of a conventional CVP analysis?

A) Learning-curve effects (i.e., productivity gains with experience) .
B) Fixed costs, in total, do not change as sales mix or total sales volume change.
C) Selling price per unit is unrelated to assumed sales volume.
D) Inputs to the profit-planning model are known with certainty.
E) Variable costs per unit are unrelated to changes in volume.