Which of the following statements is false with respect to the margin of safety?

(You may select more than one answer.)

a. The total budgeted (or actual) sales minus sales at the break-even point equals the margin of safety in dollars.

b. The margin of safety in dollars divided by the total budgeted (or actual) sales in dollars equals the margin of safety percentage.

c. In a single product company, the margin of safety in dollars divided by the variable cost per unit equals the margin of safety in units.

d. The margin of safety in dollars can be a negative number.