Cooper systems is a mobile service provider that reported net income of $250 million for the most recent fiscal year. Cooper systems had depreciation expenses of $100 million, capital expenditures of $150 million, and no interest expenses. Working capital increased by $12 million. Calculate the free cash flow for Cooper systems for the most recent fiscal year.

a. $520 million. b. -$12 million. c. $158 million. d. $188