When a vehicle is executing a turn, how do the speeds of the inner and outer drive wheels compare, and how does the differential facilitate this?

1. The outer wheel rotates faster than the inner wheel; the planet gears rotate on their spindles to allow this speed difference
2. The inner wheel rotates faster than the outer wheel; the differential locks the axles together
3. Both wheels rotate at the exact same speed; the differential slips to prevent tire wear
4. The outer wheel stops completely while the inner wheel handles all the drive torque