The correct answer is - D. It is one of the busiest airports in the country, and a diverse array of jobs need to be filled to keep the airport running.
The Hartsfield-Jackson International Airport is one of the largest airports in the United States, in fact it is ranked on the seventh place. Not that it is very large, but it has over one million flights per year, making it one of the airports with very high traffic. Because the airport is so large, and it has so many flights, lot of workers are needed for all sorts of things, be it connected directly with the flights, making ans serving food and beverages, renting cars, pretty much any other service that is offered and demanded by the travelers. It is no wonder why there are so many employees, and it is actually one of the biggest employers in Georgia.