Using the High-Low Method, the Monthly Fixed Component of Maintenance

$\begin{array}{ccc}\text { Month}&\text { Total Maintenance Cost}&\text { Production Volume (units) }\\\text { January } & \$ 1,980 & 1,850 \text { units } \\\text { February } & \$ 1,800 & 1,500 \text { units } \\\text { March } & \$ 2,200 & 2,600 \text { units } \\\text { April } & \$ 2,180 & 2,275 \text { units } \\\text { May } & \$ 2,300 & 2,750 \text { units }\end{array}$

Using the high-low method, the monthly fixed component of maintenance cost is:

A) $1,600.
B) $1,200.
C) $1,100.
D) $1,300.