The Following Data Has Been Assembled for Mildred Company The Variable Cost Per Hour Is ________

The following data has been assembled for Mildred Company.Use the high-low method.
$\begin{array}{lll}\text { Month }&\text { Cost }&\text { Hours }\\\text { January } & \$ 18,000 & 2,000 \\\text { February } & \$ 39,000 & 3,500 \\\text { March } & \$ 39,280 & 3,450 \\\text { April } & \$ 43,400 & 3,200 \\\text { May } & \$ 40,000 & 4,000\end{array}$
The variable cost per hour is ________.

A) $9.00
B) $10.00
C) $10.40
D) $11.00