To inspect slack adjusters on S-cam brakes, what is the first step a driver must take?

Answer: B — Chock the wheels and disengage the parking brake

The first step a driver must take to inspect slack adjusters on S-cam brakes is to chock the wheels and disengage the parking brake. Chocking the wheels is crucial because it provides additional safety by preventing the vehicle from rolling during inspection. This is especially important given that brakes may be engaged, and ensuring the vehicle is stable and secured is critical before proceeding with any further inspection steps. Disengaging the parking brake is also necessary to allow for proper movement and functioning of the brake components, which will facilitate a thorough examination of the slack adjusters. By following this sequence, the driver can ensure safety and accuracy while inspecting the braking system.