Select the incorrect statement regarding cost structures:

a. Faced with significant uncertainty about future revenues, a low leverage cost structure is preferable to a high leverage cost structure.

b. Highly leveraged companies will experience greater profits than companies less leveraged when sales increase.

c. The more variable cost, the higher the fluctuation in income as sales fluctuate.

d. When sales change, the amount of the corresponding change in income is affected by the company's cost structure.