You Own a Pizza Shop Called "Pizzas'R' Us If You Operate One Hour Every Day, What Is the Are

Multiple Choice

You own a pizza shop called "Pizzas'R' Us". Currently you are paying your cooks an hourly wage of $20. You sell a medium pizza for $10. By hiring more cooks, you can increase your pizza production as shown in the following table. $$\begin{array} { | l | l | } \hline \begin{array} { l } \text { Number of } \\\text { cooks }\end{array} & \begin{array} { l } \text { Total production of } \\\text { pizzas each hour }\end{array} \\\hline 0 & 0 \\\hline 1 & 4 \\\hline 2 & 7 \\\hline 3 & 9 \\\hline 4 & 10 \\\hline 5 & 10 \\\hline\end{array}$$ If you operate one hour every day, what is the marginal cost of hiring the 4^th cook?

A) $10
B) $20
C) $40
D) $60