What is the primary difference in operation between the foot brake (service brake) and the handbrake (parking brake)?

1. The foot brake operates mechanically on the front wheels; the handbrake operates hydraulically on all wheels
2. The foot brake operates hydraulically on all four wheels; the handbrake mechanically locks the rear wheels via cables
3. The foot brake is used only when parked; the handbrake is used for normal driving stops
4. There is no difference in operation between the two braking systems