What is the function of Electronic Stability Control (ESP / ESC) in modern vehicles?

1. It detects differences between the driver's steering input and the actual vehicle yaw angle, and selectively applies braking to individual wheels to counteract understeer or oversteer skids
2. It keeps the cabin at a constant temperature of 21°C
3. It increases fuel octane rating automatically during hill climbs
4. It prevents the vehicle battery from discharging when parked