During World War II, the price of rubber went up considerably. The rise in price stimulated research for alternatives. For example, today's automobile tires are almost entirely made from synthetic materials. As a result, the increase in the price of rubber eventually led to a very large drop in quantity demanded. This is an example of how the price elasticity of demand:
A) falls the less specifically the good is defined.
B) rises the less specifically the good is defined.
C) falls the greater the time frame considered.
D) rises the greater the time frame considered.