In a three-part form (A-B-A), what is the middle section typically called?

• A. B section
• B. A section
• C. C section
• D. D section

Answer: (A)

In three-part form, the A material opens the piece and then comes back at the end, with a contrasting middle section in between. That middle section is the contrasting section—the part that presents new melodies, harmony, or mood before returning to the familiar A material. In formal analysis, this middle section is typically designated as the B section to show the contrast with the opening A material. Choosing the middle as the A section would imply it’s the same as the opening material, which it isn’t. Labels like C or D would correspond to additional sections in forms that extend beyond three parts, not to the standard A-B-A structure.