A firm reports that in a certain year it had a net income of $4.5 million, depreciation expenses of $2.8 million, capital expenditures of $2.3 million, and Net Working Capital decreased by $1.5 million. What is the firm's free cash flow for that year? A) $2.4 million B) $6.5 million C) $8.1 million D) $11.1 million