What is the acceptable response for the brake pedal's behavior when repeatedly pressed with the engine off?

When the brake pedal is repeatedly pressed with the engine off, it is expected behavior for the pedal to become stiff. This stiffness occurs because, without the engine running, the brake booster—which amplifies the force applied to the brake pedal—is not operational. When you press the brake pedal, the hydraulic system still functions, but without the assistance of the booster, the pedal will require more force to be engaged effectively, leading to a stiff feeling.

As you press the pedal multiple times while the engine is off, the brake fluid creates resistance, and without the boost, there is a limited range of motion in the pedal. This is a critical test to ensure that the braking system is functioning correctly under manual conditions, which can indicate the health of the brake components when the vehicle is in operation.

The other options describe behaviors that are not expected in this context. For instance, a rising pedal indicates a hydraulic issue, a soft pedal could signify air in the brake lines or a fluid leak, and a pedal that drops to the floor would suggest severe problems such as a brake failure. Therefore, observing a stiff brake pedal upon repeated presses with the engine off is a standard and acceptable outcome.