Only one, and it has to be done in missionary position or they go to hell
They don't. Light bulbs aren't mentioned in the Bible, so they're "just a theory."
All of them: instead of getting there and changing it, they'll all clasp their hands in prayer and hope for a miracle. Guess what? Nothing happens.
None, they can't. They will be arguing about what is the mostly Godly way to do this from the Bible.
None. They just sit around praying it will get done.
Twelve, one to screw it in, and the rest to give thanks...
Zero. Real Christians will just sit around praying for the Lord to make the lightbulb work.