Healthier Living Company Manufactures Two Products-Toaster Ovens and Bread Machines

Healthier Living Company manufactures two products-toaster ovens and bread machines.The following data are available: $$\begin{array} { | l | r | r | } \hline & \text { Toaster Ovens } & \text { Bread Machines } \\\hline \text { Sales price } & \$ 80 & \$ 150 \\\hline \text { Variable costs } & \$ 60 & \$ 50 \\\hline\end{array}$$ Healthier Living can manufacture six toaster ovens per machine hour and four bread machines per machine hour.Healthier Living's production capacity is 1,800 machine hours per month.What is the contribution margin per machine hour for bread machines?

A) $20
B) $100
C) $400
D) $600