What is the primary danger of operating a motorcycle with a severely worn or loose drive chain?

1. The chain can jump off the sprockets, jamming and locking the rear wheel instantly, or snapping and shattering the engine crankcase
2. A loose chain simply slips under power and gradually wears the sprockets, with no sudden risk
3. A worn chain is safe provided it is kept well lubricated
4. Chain condition affects acceleration but has no bearing on braking or stability