Question

As we find with most songs, in poetry

Answer 1

I'd say the correct answer is A, that each couplet must rhyme.
Because B isn't correct, as there may be a specific point of view, depends on the poet.
C again isn't correct, because the meanings aren't always hidden.
And in D, it depends, some poets focus on the form of the poem, whereas they find the content irrelevant, and vice versa.