What is the correct procedure for starting a manual or automated passenger bus on a steep uphill slope to prevent rollback (坡道起步)?

1. Release the parking brake completely before touching the accelerator pedal
2. Shift into neutral, release the foot brake, and let the bus roll backward until momentum builds
3. Rev the engine to maximum RPM in third gear and abruptly drop the clutch
4. Engage the parking brake, select first gear, gently accelerate while reaching the clutch friction bite point, and smoothly release the parking brake once forward driving torque is felt