4 or 5.
A giraffic jam!
Me: Why is your question alarmingly specific 4: No reason.
Wanna go ride a bike?
None, change comes from within.
A bus driver can't change his stops.
A: Thousands because Confucious say many hands make light work.
Only one but they'll insist on going through about 5 bulbs before they find one that suits this particular room and situation.
Because they literally can't even.
Make it *sew*!