What measure is it important to take before stepping on the brake pedal in order to slow down or to stop?

1. A Ease off the accelerator and shift to lower gear.
2. B Check if there is a vehicle behind by glancing at the mirrors.
3. C Step on the clutch pedal, to reduce the engine’s fuel consumption.
4. D Signal and turn the wheel to the “hard shoulder”, to avoid rear-end collision.