The story of Adam and Eve doesn't present us with a choice. It isn't set up for us to understand that we should not take the fruit. We aren't given that option in life. We are creatures who have good and evil knowledge. It's in us. That's the story.
But Cain & Abel are choices.
The choices of Abel and Cain are not "be good / be wicked."
The choices are "trust God, even if it means dying / trust yourself, even if it means murdering."
