I think either A or D. Which one is it? Please help, this is my second time taking this and I don't wanna fail!

Read these sentences from Twain's memoir:

"It was a good enough lesson, but learned the hard way. Yet about the hardest part of it was that for months I so often had to hear a phrase which I conceived a particular distaste for. It was, 'Oh, Ben, if you love me, back her!'"

How do lines such as these affect the tone of "A Cub Pilot"?

A. They show that the author now understands the importance of the lesson.
B. They show that the author misses his days as a riverboat's pilot.
C. They show that the author resents his coworkers' teasing.
D. They show that the author now regards the events with humor.