Which of the following sentences from the section "The Limits To Free Enterprise With A Mixed Economy" BEST develops a central idea of the article?

A

In addition, the government often is asked to get involved in the economy to correct situations in which the price system does not work.

B

A natural monopoly is a type of market dominance that exists due to the high startup costs of conducting a business in a specific industry.

C

The government pays much of the cost of medical care for the aged and those who live in poverty.

D

In this mixed economy, individuals can help guide the economy.