Bubba Ho-Tep Company reported net income of $290 million for the most recent fiscal year. The firm had depreciation expenses of $100 million and capital expenditures of $150 million. Although it had no interest expense, the firm did have an increase in net working capital of $30 million. What is Bubba Ho-Tep's free cash flow?
选项：

A:$10 million
B:$210 million
C:$270 million
D:$570 million