Based on the corporate valuation model, Wang Inc.'s total corporate value is $690 million. Its balance sheet shows $90 million notes payable, $180 million of long-term debt, $40 million of common stock (par plus paid-in-capital), and $160 million of retained earnings. What is the best estimate for the firm's value of equity (in millions)? a. 5600 million O b. $420 million c. $510 million O d. $530 million e. $460 million