Common resources tend to be overused because:

a) individuals tend to ignore the cost their use of the resource has on others.
b) the marginal cost of allowing one more unit of consumption is zero.
c) the individual marginal cost is greater than the marginal social cost.
d) the marginal social cost of using the resource is below the marginal social benefit at the market equilibrium.
e) common resources are nonrival and nonexcludable.