Assume that each day ten thousand children watch Sesame Street on public television and that watching Sesame Street generates a benefit of $100 per child per year. Once a year, public television hold a pledge drive asking viewers to make voluntary contributions in order to keep the programming available to everyone. If public television stations collect less than $100 per child during the pledge drive, then this is evidence:

A. that parents do not care about their children.
B. that head taxes are regressive.
C. that the government should not subsidize public television.
D. of the free-rider problem.

Answer: D