The Following Data Pertain to Activity and Utilities Costs for Two

The following data pertain to activity and utilities costs for two recent years:
$\begin{array}{|l|r|r|}\hline & \text { Year 2 } & \text { Year 1 } \\\hline \text { Activity Level in Units } & 12,000 & 8,000 \\\hline \text { Utilities Cost } & \$ 15,000 & \$ 12,000 \\\hline\end{array}$
Using the high-low method,what is the variable cost per unit for utilities?

A) $1.25 per unit.
B) $1.50 per unit.
C) $1.33 per unit.
D) $0.75 per unit.