The lyric “The hills are alive with the sound of…” ends with “music.”
Richard Rodgers and Oscar Hammerstein II wrote the song for the 1959 musical The Sound of Music. Maria sings it while expressing her delight in the Austrian landscape and her lifelong connection to music.
Julie Andrews performed the song in the 1965 film adaptation. The movie’s opening sequence, filmed against the Alps, helped turn the lyric into an internationally recognized musical moment.
Because “singing” and “echoes” fit the imagery, they can seem plausible in a quiz. The canonical line uses “music,” repeating the title’s central idea.