A couplet consists of two consecutive lines of verse that typically rhyme and have the same meter. In the options given, the lines that form a couplet are:
A. "If this be error and upon me proved,
I never writ, nor no man ever loved."
The lines in A both rhyme and share a similar meter, making them a couplet. The other options do not form couplets, as they do not consist of two consecutive lines paired together.