Price(dоllаrs) Quаntity supplied(mаrginal sоcial cоst) Quantity demanded(marginal social benefit) 0 0 31 1 4 28 2 8 24 3 12 20 4 16 16 5 20 12 6 24 8 7 28 4 8 32 0 Based on the above table, which of the following is the efficient quantity of output?