Verified Answer :

Byron uses the final couplet in each stanza to 

a. create a punch line. 

Byron uses a specific poetic structure identified as Ottava Rima. It has a rhyme scheme of ABABABCC where each letter stands for the lines' end rhyme.  Its rhythmic pattern is in iambic pentameter. 

The couplet is represented by CC. These lines 
give a humorous conclusion to the six lines that come before it. In short, these lines are the punch lines.
 

anonnn

the correct answer is a!!