At the Current Level of Output, the Marginal Social Cost

Multiple Choice

At the current level of output, the marginal social cost of paper is $30 per ton and its marginal private cost is $20 per ton. The marginal social benefit from paper is $20 per ton. The market for paper is competitive and unregulated. This means that at the current level of production,

A) the market for paper is in equilibrium.
B) the efficient quantity of paper is produced.
C) there is a shortage of paper.
D) the quantity of paper produced is less than the efficient level of output.