The Following Information Was Available for the Year Ended December

The following information was available for the year ended December 31, 2019: $\begin{array}{lr}\text { Net sales } & \$ 300,000 \\\text { Cost of goods sold } & 210,000 \\\text { Average accounts receivable for the year } & 15,000 \\ \text { Accounts receivable at year-end } & 18,000 \\\text { Average inventory for the year } & 60,000 \\\text { Inventory at year-end } & 70,000\end{array}$ The number of days' sales in accounts receivable for 2019, using year- end accounts receivable were:

A) 18.3 days
B) 21.9 days
C) 26.1 days
D) 31.1 days