Consider a retailing firm with a net profit margin of 3.6%, a total asset turnover of 1.76, total assets of $449 million, and a book value of equity of $18.9 million. a. What is the firm's current ROE? b. If the firm increased its net profit margin to 4.1%, what would be its ROE? c. If, in addition, the firm increased its revenues by 16% (while maintaining this higher profit margin and without changing its assets or liabilities), what would be its ROE