The Following Is Allison Corporation's Contribution Format Income Statement for Last

The following is Allison Corporation's contribution format income statement for last month:
$\begin{array}{|l|r|}\hline \text { Sales } & \$ 800,000 \\\hline \text { Less: variable expenses } & \underline{300,000} \\\hline \text { Contribution margin } & 500,000 \\\hline \text { Less: fixed expenses } & \underline{400,000} \\\hline \text { Operating income } & \$ 100,000 \\\hline\end{array}$ The company has no beginning or ending inventories. The company produced and sold 10,000 units last month.


-If sales increase by 200 units,by how much should before-tax profits increase?

A) $16,000.
B) $5,000.
C) $2,000.
D) $10,000.