Which line from Act II of The Importance of Being Earnest is an epigram?

“I am not sure, however, that the news inspires me with feelings of unmixed delight.”
“It is always painful to part from people whom one has known for a very brief space of time.”
“You must remember his constant anxiety about that unfortunate young man his brother.”
“Were I fortunate enough to be Miss Prism’s pupil, I would hang upon her lips.”