When parking and leaving a car what should you do?

Answer: B — Engage the steering lock

When parking and leaving a car, it is important to engage the steering lock to prevent the vehicle from being easily stolen. Leaving the windows open (A) or the keys in the ignition (C) can increase the risk of theft. Turning on the hazard lights (D) is not necessary for parking and can drain the car's battery. Therefore, option B is the most appropriate and safest action to take.