Buffalo in the United States almost became extinct while cattle, an animal that provides similar products, never has been close to extinction. The difference is due to

A) the greater marginal value of a head of cattle relative to buffalo, leading to over-hunting of buffalo.
B) the greater marginal value of a buffalo relative to a steer, leading to the overharvesting of buffalo.
C) cattle existing in Europe also while buffalo were specific to North America.
D) the use of private property rights on cattle and common property rights on buffalo.

Answer: D