As we find with most songs, in poetry
a. meanings are hidden in imprecise words.
b. each couplet must rhyme.
c. there's no specific point of view.
d. sound and content have equal weight

The question is asking to choose among the following choices that state the characteristic that we find mostly in most songs and also in poetry, base on my research and further investigation, I would say that the answer would be in letter  B. each couplet must rhyme. I hope you are satisfied with my answer 

Pop music is music that is popular made by popular artists

Iwould go with write exactly two extra paragraphs to point out additional information. but the keyword "exactly" throws me off. leads me to believe it's d. go with your gut feeling. either "write exactly two extra paragraphs" or "none of these".