None. They don't have lightbulbs in caves
Trick question. Idiots can't screw in lightbulbs regardless of help from other idiots.
Virgos don't have time to change their own lightbulbs. They're too busy changing them for everyone else.
Whatever it says in the book.
Just two, as long as they can find a way in.
Is there a terrorist mobile tariff I can go on
None, they don't use light bulbs. They live in caves and use no forms of artificial energy because they wouldn't want to be perceived as hypocrites or morons.