How can you prevent a truck from rolling back when starting on a hill?

Answer: B — Engage the parking brake and use the accelerator

To prevent a truck from rolling back when starting on a hill, engaging the parking brake and using the accelerator is the most effective method. When you engage the parking brake, it holds the truck securely in place, allowing you to focus on smoothly applying power without the fear of rolling back. As you prepare to start moving, you can gently release the brake while simultaneously applying the accelerator. This coordinated action helps to ensure that the truck moves forward without losing traction or control, particularly on a slope. While the other options might seem beneficial in different contexts, they do not adequately address the specific concern of rolling backward on an incline. Shifting to neutral could lead to unintended movement. Accelerating quickly without preparing with the brake could cause a sudden roll back if control is not managed. Waiting for a green light is irrelevant to this scenario as it does not take into account the specific conditions of starting on a hill. Hence, the combination of the parking brake and careful throttle management is the safest approach for starting on an incline.