Window Shine Is Provides Window Cleaning Service Using the High-Low Method, What Is the Amount of Total

Window Shine is provides window cleaning service. Information concerning costs and number of windows cleaned for three months during 2014 appear below: $\begin{array}{clr}\text { Month }&\text { Activity }& \text { Cost }\\\text { May } & 18,000 \text { windows } & \$ 84,000 \\\text { July } & 21,000 \text { windows } & 94,500 \\\text { September } & 20,400 \text { windows } & 94,800\end{array}$ Using the high-low method, what is the amount of total fixed costs?

A) $10,500
B) $3,000
C) $21,000
D) $78,857