Another big impetus for the evolution of the AC radio format was the popularity of easy listening or "beautiful music" stations, stations with music specifically designed to be purely ambient. Whereas most easy listening music was instrumental, created by relatively unknown artists, and rarely purchased, AC was an attempt to create a similar "lite" format by choosing certain tracks (both hit singles and album cuts) of popular artists.
What types of tracks from popular artists did adult contemporary radio play?
hit singles and album cuts