Santa Fe Tile Company Had the Following Inventory Purchases and Sales

Santa Fe Tile Company had the following inventory purchases and sales during the month of May.The company uses the periodic inventory method. $$\begin{array} { | c | c | c | c | c | c | c | } \hline & \text { Purchases } & & & \text { Sales } & & \\\hline \text { Date } & \text { Units } & \text { Unit Cost } & \text { Total } & \text { Units } & \text { Unit Price } & \text { Total } \\\hline \text { May 1 } & 100 & \$ 4 & \$ 400 & & & \\\hline 5 & 200 & 5 & 1,000 & & & \\\hline 10 & & & & 100 & \$ 10 & \$ 1,000 \\\hline 15 & 100 & 6 & 600 & & & \\\hline 20 & 150 & 7 & 1,050 & & & \\\hline 25 & & & & 200 & 11 & \$ 2,200 \\\hline 30 & 160 & 8 & 1,280 & & & \\\hline & 710 & & \$ 4,330 & 300 & & \$ 3,200 \\\hline\end{array}$$
- If Santa Fe uses average-cost,how much was the Cost of goods sold for the month?

A) $1,400
B) $1,850
C) $1,380
D) $1,615