With Which Unit of Labor Do Diminishing Marginal Returns First

Multiple Choice

$$\begin{array}{l}\begin{array} { | c | c | } \hline \text { Units of Labor } & \text { Units of Output } \\\hline 0 & 0 \\\hline 1 & 15 \\\hline 2 & 35 \\\hline 3 & 45 \\\hline 4 & 52 \\\hline\end{array}\\\text { Table 21.1 }\end{array}$$ With which unit of labor do diminishing marginal returns first appear in Table 21.1?

A) The first.
B) The second.
C) The third.
D) The fourth.