Bubba Ho Tep Company reported net income of $300 million for the most recent fiscal year. The firm had depreciation expenses of $125 million and capital expenditures of $150 million. Although it had no interest expense, the firm did have an increase in net working capital of $20 million. What is Bubba Ho Tep's free cash flow?
a. 170 million
b. 255 million
c. 150 million
d. 5 million