"If this be error and upon me proved,/I never writ, nor no man ever loved."

What is the impact of these concluding lines from Shakespeares's Sonnet 116?

a. They underscore the fact that everyone makes mistakes.
b. They underscore the fact that Shakespeare is a writer.
c. They underscore the conviction that emotions are unreliable.
d. They underscore the conviction of everything stated before.