Music appreciation

A theme is a melodic idea that's

A. of lesser importance than other musical ideas.

B. a two-measure song.

C. always in a minor key.

D. stated and restated in different forms.

In my opinion, the correct answer is D. stated and restated in different forms. A theme isn't of lesser importance - on the contrary, it often forms the melodic spine of a work, e. g. a sonata or a symphony. It may recur many times throughout the work, in many different forms, with a changed tonality, another key, extended or shortened versions ...