Identify a common structure used in pop music.

The verse-chorus structure is a fundamental framework often employed in pop music, distinguishing it from other styles. This structure involves alternating sections of verses, which typically introduce the narrative or themes of the song, with the chorus, which encapsulates the main message or hook. The repetition of the chorus allows it to be memorable and catchy, often making it the focal point of the song. This format contributes to the song's accessibility and is effective in engaging listeners, enhancing the overall appeal of pop music.

The other options represent different musical forms or structures that are not as commonplace in pop music. Theme and variations are often used in classical music, the 12-bar blues is a staple in blues and jazz genres, and sonata form is primarily associated with classical music compositions, particularly in the structure of symphonies and sonatas. These forms do not reflect the typical characteristics and commercial appeal found in mainstream pop songs.