The North Division of the Lyman Company reported the following data for last year:

Net operating income …………………...…………….. $ 200,000

Interest expense ……………………………....……......... $ 50.000

Tax expense ………………………………………..........….. $ 60,000

Stockholders' equity ……………………………….....….$ 250,000

Average operating assets …………………………..….$ 500.000

Minimum required rate of return ……………………….. .. 14%

The return on investment last year for the North Division was:

a. 18%

b. 40%

c. 36%

d. 80%