Why Is a Construction Worker Never Likely to Earn as Much

Multiple Choice

Why is a construction worker never likely to earn as much as a famous athlete?

A) Compensating differentials create a higher wage for professional athletes.
B) Technological progress has advanced less in the construction industry then in sports training.
C) Productivity levels are low in the construction industry due to the high number of people willing to be construction workers.
D) A construction worker can provide his services to only a limited number of customers.