The Table Below Shows the Marginal Costs and Marginal Benefits

The table below shows the marginal costs and marginal benefits associated with cleaning up a polluted landfill site.
TABLE 17-2
-Refer to Table 17-2.What is the net benefit to society of achieving the 20th percentage point of cleanliness of this land?

A) $17.75 million
B) $9.0 million
C) $18.25 million
D) $7.5 million
E) -$7.5 million