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