Read this and answer the question. If the question is unanswerable, say "unanswerable".

Adult contemporary music (AC) is a style of music, ranging from 1960s vocal and 1970s soft rock music to predominantly ballad-heavy music of the present day, with varying degrees of easy listening, pop, soul, rhythm and blues, quiet storm, and rock influence. Adult contemporary is rather a continuation of the easy listening and soft rock style that became popular in the 1960s and 1970s with some adjustments that reflect the evolution of pop/rock music.

What does the acronym AC stand for?
Adult contemporary