$($Break$-$even point and operating leverage$)$ Rockstar, Inc. manufactures a complete line of men's and women's casual shoes for independent merchants. The average selling price of its finished product is $575$ per pair. The variable cost for this same pair of shoes is $$60.$ Footwear Inc. incurs fixed costs of $$170,000$ per year.a$.$ What is the break$-$even point in pairs of shoes sold for the company?b$.$ What is the dollar sales volume the firm must achieve to reach the break even point?c$.$ What would be the firm's operating profit or loss $($that is$,$ net operating income$)$ at the following units of production sold: $7,000$ pairs of shoes? $12,000$ pairs of shoes? $15,000$ pairs of shoes?