Refer to Figure 15.1. From society's point of view, the efficient level of output is

A) 20 haircuts.
B) 23 haircuts.
C) 25 haircuts.
D) 30 haircuts.

The efficient level of output from society's point of view is where the marginal social benefit equals the marginal social cost. Without seeing Figure 15.1, this principle typically guides the identification of the efficient output level, which is often depicted as the point where the demand curve (representing marginal social benefit) intersects the supply curve (representing marginal social cost). Given the options, 25 haircuts is chosen based on this economic principle, assuming it corresponds to that equilibrium point in the figure.