What is the main messages of the underlined sentence? construction of the areanas and stadiums where the competitive events will take place, as well as lodging for the athletes, creates thousands of jobs.

A: Athletes need places to compete and sleep in a host city, as well as jobs after games.

B: it is often difficult to decide where new buildings should be constructed in a host city.

C: The creation of new structures for the games is the main responsibility of a host city.

D: A host city's need for new buildings creates many employment opportunities.