The Table Below Shows the Marginal Benefit and Marginal Cost

The table below shows the marginal benefit and marginal cost of pollution abatement for an economy. $$\begin{array} { | c | c | c | } \hline \begin{array} { c } \text { Units of } \\\text { Pollution } \\\text { Abatement }\end{array} & \mathrm { MB } & \mathrm { MC } \\\hline 1 & 120 & 5 \\\hline 2 & 115 & 15 \\\hline 3 & 105 & 30 \\\hline 4 & 90 & 50 \\\hline 5 & 70 & 70 \\\hline 6 & 45 & 95 \\\hline 7 & 15 & 125 \\\hline 8 & 0 & 155 \\\hline\end{array}$$ TABLE 17- 1
-Refer to Table 17- 1.Suppose a public authority has the mandate to maximize social welfare by choosing the appropriate amount of pollution abatement.The marginal cost of reducing pollution by one unit is _ at a(n) rate.

A) decreasing; decreasing
B) increasing; decreasing
C) decreasing; reduced
D) increasing; increasing
E) increasing; constant