What is the typical correct drive chain slack (free play) for most street motorcycles when checked midway between the front and rear sprockets on the bottom run?

1. 0 mm (completely tight with zero deflection like a guitar string)
2. 20 to 30 mm (or as specified in the manufacturer owner's manual)
3. 100 to 150 mm (hanging loosely below the exhaust pipe)
4. Over 200 mm to ensure the chain can easily slide off the sprockets