Taxi Cab Drivers in Large Cities Are Likely to Earn

Taxi cab drivers in large cities are likely to earn more than taxi cab drivers in rural areas.One reason for this wage differential could be that

A) driving in large cities is more dangerous than driving in rural areas.
B) driving in large cities is more fun than driving in rural areas.
C) driving in large cities is easier than driving in rural areas.
D) it is unlikely that a taxi cab driver in a large city will be involved in a traffic accident with farm animals.