John proctor’s dilemma culminated with him confessing to witchcraft, even though

The answers for this question are:
He realized that in doing so he would ruin his reputation forever.
He realized that all he had was his good name & reputation.
Elizabeth approved of whatever he decided.

During that time, people were punishable by law if they're proven to conduct any form of actions that indicated 'dark magic'. Often times, local citizen put the matters into their own hands and would burn those who did these kind of things alive, so confessing to withcraft was a really hard thing to do.