Polly estimates that if she spends another $10,000 to upgrade the computer equipment at her tax preparation company, the number of tax returns she can handle will increase from 200 to 280 . She charges an average of $50 to do each tax return. The MRP per dollar of this $10,000 upgrade is

a. $10,000
b. 25 percent
c. $4,000
d. 100 percent
e. 40 percent

E