A. ballet: music
B. meter: poetry
C. solo: ensemble
D. biography: history
E. documentary: event

(Choose a pair that expresses a relationship most similar to that of the given pair.)

As far as I know, ballet not only means a dance form, but also means the music for this dance form. So I think A is the right answer. However the answer provided is D.

What do you think? Thank you.
Not only is portrait a sub-category of painting, it is a category that focuses on an individual human being.
A portrait is the painting of one particular person.

A biography is the history of one particular person.
Teachers: We supply a list of EFL job vacancies
Thank you, davkett. Biography is a sub-category of history too? I need your detailed explanation. Emotion: smile
 nona the brit's reply was promoted to an answer.
Site Hint: Check out our list of pronunciation videos.
I can't do better than n-the-b.