A firm has net sales of $$65,000,$ operating expenses of $$21,300,$ depreciation of $$5,000,$ cost of goods sold of $$36,500,$ and interest expense of $$4,500.$ What is the operating margin?

A$)9\mathrm{.}2\%$

B$)-2\mathrm{.}8\%$

C$)10\mathrm{.}3\%$

D$)2\mathrm{.}6\%$

E$)3\mathrm{.}4\%$

Explain why the correct answer is E$)$