What does the brake system use to transfer force from the pedal to the braking components?

The reason hydraulic fluid is the correct answer relates to how modern brake systems are designed to operate efficiently and effectively. In a hydraulic brake system, pressing the brake pedal creates force that is transmitted through the hydraulic fluid in the brake lines. This fluid is incompressible, meaning that when force is applied at one end (the brake pedal), it is evenly distributed throughout the fluid, allowing for amplification of that initial force to each braking component.

The hydraulic system technically translates the driver's intention into a functional response, generating sufficient force to engage the brakes at the wheels. This mechanism also enables smoother and more responsive braking action, particularly in vehicles equipped with anti-lock braking systems (ABS), which makes use of the same hydraulic principles.

Other systems mentioned, while they do exist in different contexts, do not apply in the same way for traditional vehicle braking systems. Mechanical levers may assist in some setups, pneumatic pressure might be utilized in specific air brake systems typically found on larger vehicles such as trucks, and electric signals are relevant in electronic braking systems but do not replace the fundamental mechanics of force transfer through hydraulic fluid in standard automotive applications.