Charlie Shine has written a self-improvement book. The following are its pricing and cost details:

Selling price$18.00 per book

Variable costs per unit:

Production$3.50

Selling and administrative$1.90

Fixed costs:

Production$33,600 per year

Selling and administrative15,540 per year

Assume the variable production cost and the selling price were each increased by $0.30 per book. Which of the following would change?

A.Break-even point in units

B.Contribution margin ratio

C.Total fixed costs

D. Contribution margin per unit