Answer:
D. A resource that can be replaced naturally within a reasonable time
period
Explanation:
A renewable resource is a resource that are naturally replenished in a reasonably short amount of time. There is virtually an endless supply of renewable resources. Some examples include solar energy, water power and wind power.
A and C are incorrect because the cost of the resource does not determine if it is renewable or not. B is incorrect, because renewable resources do not take many years to replace. Therefore D. A resource that can be replaced naturally within a reasonable time period, is correct.