Which of the following is the correct formula to calculate inventory turnover?

A$.$ Inventory turnover $=$ Cost of Goods Sold $-$ Average merchandise inventory

B$.$ Inventory turnover $=$ Cost of Goods Sold $$ Average merchandise inventory

C$.$ Inventory turnover $=$ Cost of Goods Sold $+$ Average merchandise inventory

D$.$ Inventory turnover $=$ Cost of Goods Sold $\frac{?}{?}$ Average merchandise inventory