Assume Manfred's Shoe Shine Parlor Hires Labor, Its Only Variable

Multiple Choice

Assume Manfred's Shoe Shine Parlor hires labor, its only variable input, under purely competitive conditions. Shoe shines are also sold competitively. $\begin{array} {| c | c | c | c|} \text { Units of Labor } & \text { Total Product } & \begin{array} { c } \text { Marginal } \\\text { Product }\end{array} & \begin{array} { c } \text { Total } \\\text { Revenue }\end{array} \\\hline 0 & 0 & & \\\hline 1 & 14 & 14 & \$ 42 \\\hline 2 & & 10 & \\\hline 3 & 30 & & 90 \\\hline 4 & 35 & & \\\hline 5 & 39 & & 117 \\\hline 6 & & & 126 \\\hline 7 & 44 & 2 & 132 \\\hline\end{array}$ What is the marginal product of the sixth worker?

A) 2 units
B) 3 units
C) 4 units
D) 5 units