A Company sells a single product. The selling price is $15 per unit and the contribution margin ratio is 40 percent. Management has decided to reduce the selling price by 20 percent (from $15 to $12 per unit) in an effort to increase sales volume. As a result of this 20 percent decrease in the selling price, management can expect that

a) sales volume will increase by 20 percent.
b) the contribution margin ratio will decrease from 40 percent to 20 percent.
c) the contribution margin ratio will remain unchanged at 40 percent.
d) the contribution margin ratio will decrease from 40 percent to 25 percent