In my opinion, the correct answer is <span>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... </span>
expressed and repeated in various structures. A topic isn't of lesser significance unexpectedly, it frequently shapes the melodic spine of a work, e.g. a sonata or an orchestra. It might repeat commonly all through the work, in various structures, with a changed tonality, another key, broadened or abbreviated variants.
