Which of the following statements is true?

A) When the forces of supply and demand determine for whom goods are produced in a society,an equitable distribution of income will naturally result.
B) An external benefit will occur when a third party enjoys some of the benefits derived from production of some good or service.
C) One of the roles of our government is to provide a job to any able-bodied person who wants a job.
D) The price mechanism will work well if there are at least two companies that are competing against each other.

External benefits occur when third parties benefit from the production of a good or service without paying for it. This is a market failure because the market does not account for the full social benefit of the good or service. The other statements are not true. The forces of supply and demand do not necessarily lead to an equitable distribution of income, the government's role in the economy is debated and providing a job to anyone who wants one may not be feasible or desirable, and having at least two competing companies may not be enough to ensure price mechanism works well.