Thane Company Is Interested in Establishing the Relationship Between Electricity

Thane Company is interested in establishing the relationship between electricity costs and machine hours.Data have been collected and a regression analysis prepared using Excel.The monthly data and the regression output follow: $$\begin{array} { | l | r | r | } \hline \text { Month } & \text { Machine Hours } & \text { Electricity Costs } \\\hline \text { January } & 2,500 & 18,400 \\\hline \text { February } & 2,900 & 21,000 \\\hline \text { March } & 1,900 & 13,500 \\\hline \text { April } & 3,100 & 23,000 \\\hline \text { May } & 3,800 & 28,250 \\\hline \text { June } & 3,300 & 22,000 \\\hline \text { Juby } & 4,100 & 24,750 \\\hline \text { August } & 3,500 & 22,750 \\\hline \text { September } & 2,000 & 15,500 \\\hline \text { October } & 3,700 & 26,000 \\\hline \text { November } & 4,700 & 31,000 \\\hline \text { December } & 4,200 & 27,750 \\\hline\end{array}$$

If the controller uses the high-low method to estimate costs,the variable cost per machine hour is:

A) $6.25.
B) $6.90.
C) $5.77.
D) $11.70.