What can happen if you do not leave extra space when stopped on a hill?

Answer: A — The vehicle ahead might roll back when starting

If you do not leave extra space when stopped on a hill, the correct answer is that the vehicle ahead might roll back when starting. Leaving extra space on a hill is essential because it provides a buffer in case the vehicle in front of you rolls back when they start moving again. This extra space gives you the necessary time and distance to react, preventing a potential collision or accident. Options B, C, and D are not directly related to the consequences of not leaving extra space when stopped on a hill. Overheating, blocking an intersection, and traffic light timing are important factors to consider while driving, but they are not directly impacted by the space you leave between vehicles on a hill.