As I see it, the only line that makes up a rhyming couplet is C."So I stared at the Night! And she / Stared back solemnly at me!". Well, it’s easy to catch the beat, you just need to read all the words aloud with pauses and all the punctuation marks. In that case we have two rhyming words, they are ‘’she’’ and ‘’me’’, you need to focus on the pause after ‘’she’’ and everything will be clear.
