What occurs if the hydraulic brakes fail?

Answer: A — The parking brake activates to stop the vehicle

When hydraulic brakes fail, the correct scenario involves the parking brake becoming the primary means to stop the vehicle. Hydraulic brakes are designed to transmit force through brake fluid, allowing the driver to slow down or stop the vehicle effectively. If this system fails, either through fluid loss or a mechanical issue, the parking brake can be engaged to help bring the vehicle to a halt. While the ignition system and coasting to a stop do not directly serve as alternatives for stopping the vehicle in cases of brake failure, relying on the parking brake provides a safety measure to avert accidents. Engaging the parking brake helps create enough friction to slow down the vehicle, highlighting its significance as a backup safety feature.