Which statement correctly defines "ternary" form?

A. an ancient musical form (surviving into the twenty-first century) in which a refrain alternates with contrasting material
B. a contrapuntal form in which the individual voices enter and each in turn duplicates exactly the melody that the first voice played or sang
C. a three-part musical form in which the third section is a repeat of the first, hence ABA
D. a musical form often used in setting a strophic, or stanzaic, text, such as a hymn or a carol; the music is repeated anew for each successive strophe
E. a musical form in which a theme continually returns but is varied by changing the notes of the melody, the harmony, the rhythm, or some other feature of the music