The smallest unit of musical form that makes sense on its own is a

A. period.

B. phrase.

C. cadence.

D. measure.

A period. thats the answer

The correct answer is B. phrase

The definition that it is the smallest unit that can make sense on its own was made by John D. White, but the idea existed for much much longer and was seen even in ancient times, although it differed then because the understanding of musical meter was different at that time.