hi, answer all of them please

At a sales level of $90,000, Sun Company's contribution margin is $24,000. If the degree of operating leverage is 5 at a $90,000 sales level, net operating income must equal: a. $4,000 b. $6,000 c. $11,200 d. $14,500 e. $4,800 Fortuna Corporation's operating leverage is 7.3. If the company's sales increase by 12%, its net operating income should increase by about: a. 73.12% b. 65.14% c. 50.05% d. 44.40% e. 87.60% Tarik Company has sales of 1,000 units at $70 a unit. Variable expenses are 30% of the selling price. If total fixed expenses are $30,000, the degree of operating leverage is: a. 4.16 b. 2.58 c. 2.96 d. 3.15 e. 3.50