The given answer, AFC, is the correct answer because the Indianapolis Colts are a team in the National Football League (NFL) and they belong to the AFC (American Football Conference) division. The NFL is divided into two conferences, the AFC and the NFC (National Football Conference), and each conference is further divided into divisions. The Colts are part of the AFC South division, along with the Houston Texans, Jacksonville Jaguars, and Tennessee Titans. Therefore, the Colts are classified under the AFC conference.