Refer to the Table Below A)1
B)3
C)4
D)6

Refer to the table below. According to the Cost-Benefit Principle, how many units of this activity should be carried out? $$\begin{array} { | c | c | c | } \hline \begin{array} { c } \text { Units of } \\\text { Activity }\end{array} & \begin{array} { c } \text { Total } \\\text { Cost }\end{array} & \begin{array} { c } \text { Total } \\\text { Benefit }\end{array} \\\hline 0 & \$ 0 & \$ 0 \\\hline 1 & \$ 30 & \$ 100 \\\hline 2 & \$ 40 & \$ 160 \\\hline 3 & \$ 60 & \$ 190 \\\hline 4 & \$ 100 & \$ 210 \\\hline 5 & \$ 150 & \$ 220 \\\hline 6 & \$ 210 & \$ 225 \\\hline\end{array}$$

A) 1
B) 3
C) 4
D) 6