$\text { Harstin Corporation has provided the following data for the past year: }$

$\text { Harstin Corporation has provided the following data for the past year: }$
$\begin{array}{|l|r|}\hline \text { Sales } & \$ 625,000 \\\hline \text { Gross Margin } & \$ 70,000 \\\hline \text { Operating Income } & \$ 50,000 \\\hline \text { Shareholders' Equity } & \$ 90,000 \\\hline \text { Average Operating Assets } & \$ 250,000 \\\hline \text { Residual Income } & \$ 20,000\\\hline\end{array}$
-What was the return on investment for the past year?

A) 8%.
B) 20%.
C) 28%.
D) 36%.