Amazonia Inc is an all equity firm that generated $100 million in net income during the course of the year. The firm had capital expenditures of $80 million, deprecation of $20 million and an increase in working capital expenditures of $10 million. If the cash balance at the firm increased by $20 million during the course of the year, how much cash did the firm return to its stockholders? Select one: a. $30 million b. $ 10 million c. $ 20 million d. $ 5 million