When driving down a very long and steep mountain descent in Cameroon, how should a driver use the vehicle's transmission and braking system to maintain safety?

1. Select a low gear (rapport inférieur) to utilize engine braking and apply the footbrake periodically in firm bursts rather than riding it continuously
2. Shift into neutral and apply continuous light pressure on the footbrake throughout the entire descent
3. Switch off the ignition engine key to save fuel while descending
4. Keep the vehicle in top gear and rely solely on the parking handbrake