William B. Hartsfield was a man of humble origins who became one of the greatest mayors of Atlanta. He served as mayor for six terms (1937–41, 1942–61), longer than any other person in the city's history. Hartsfield held office during a critical period when the color line separating the races began to change and the city grew . . . to a metropolitan population of one million. He is credited with developing Atlanta into the aviation powerhouse that it is today . . . . . . . On August 30, 1961, the city peacefully integrated its public schools. As a result, Atlanta began to acquire its reputation as "A City Too Busy to Hate." –New Georgia Encyclopedia

During Hartsfield’s time in office, Atlanta became known as "A City Too Busy to Hate.” What factors supported this nickname? Check all that apply.

The city integrated its schools.
Atlanta became a leader in aviation.
The economy declined.
The population increased to one million.
Many people served as the city mayor.