The Table Below Shows the Marginal Benefit and Marginal Cost

The table below shows the marginal benefit and marginal cost of purchasing an additional unit of 3 different public goods. $$\begin{array} { | c | c | r | r | } \hline & \text { Mar ginal benefit } & \text { Marginal cost } & { \text { Total spending an the public } } \\\hline \text { Public pood 1 } & \$ 20 & \$ 20 & \$ 1,500 \\\hline \text { Public pood 2 } & \$ 15 & \$ 25 & \$ 800 \\\hline \text { Public pood 3 } & \$ 10 & \$ 5 & \$ 700 \\\hline\end{array}$$  
The government is spending the socially optimal amount on:

A) public good 1.
B) public good 2.
C) public good 3.
D) public good 1 and public good 2.