Use the Following to Answer Questions -(Table: Coal Mine Pollution)Use Table: Coal Mine Pollution

Use the following to answer questions : $$\begin{array}{l}\text { Table: Coal Mine Pollution }\\\begin{array} { c c c } \hline \begin{array} { l } \text { Quantity of } \\\text { Pollution } \\\text { (tons) }\end{array} & \begin{array} { c } \text { Marginal } \\\text { Social } \\\text { Benefit }\end{array} & \begin{array} { c } \text { Marginal } \\\text { Social } \\\text { Cost }\end{array} \\\hline 0 & \$ 800 & \$ 0 \\1 & 700 & 100 \\2 & 600 & 200 \\3 & 500 & 300 \\4 & 400 & 400 \\5 & 300 & 500 \\6 & 200 & 600 \\7 & 100 & 700 \\8 & 0 & 800 \\\hline\end{array}\end{array}$$
-(Table: Coal Mine Pollution) Use Table: Coal Mine Pollution.The table shows the marginal social benefit and cost of various amounts of pollution from a coal mine.From the perspective of efficiency,2 tonnes of pollution is:

A) too much.
B) the efficient amount.
C) not enough.
D) the socially optimum amount.