need help on 5 and 6

Question 5 (1 point) What is the firm's optimal capital structure? OA) D/A = 20 B) D/A=.30 C) D/A = 40 OD) D/A-50 E) D/A-60 Alpha Resources Inc. has sales revenue of $800,000, operating costs of $350,000, and depreciation expense of $20,000. The company has $475,000 of outstanding bonds that pay 5% interest and it faces an average state-plus-federal tax rate of 40%, what is its net income? A) $96.000 B) $214,500 C) $219,000 D) $243,750 E) $314.250