What should you do if your vehicle stalls and efforts to restart fail?

Answer: B — Remain calm and assess your surroundings

If your vehicle stalls and efforts to restart fail, remaining calm and assessing your surroundings is the most appropriate response. This action allows you to evaluate your situation, including the location of your vehicle, the flow of traffic, and any potential hazards around you. By staying calm, you can think more clearly and make safer decisions regarding what to do next. Assessing your surroundings may involve determining whether it's safe to exit the vehicle, if you can notify other drivers about your situation, or if you need to call for roadside assistance. This step is crucial as it helps prevent accidents or further complications. In contrast, turning on the radio is unlikely to be beneficial in a stalled vehicle situation, while pushing the vehicle could be dangerous, especially in heavy traffic or on a busy road. It's important to prioritize safety for both yourself and other road users, making a calm assessment the best approach in such circumstances.