You're stationary. The brake air-pressure warning light comes on. Why should you keep the parking brake on? You're stationary. The brake air-pressure warning light comes on. Why should you keep the parking brake on?

• Possible answers:

   
• A. Because the vehicle will suddenly roll backwards
• B. Because it will cause the air pressure to rise
• C. Because the service brake may not stop you
• D. Because it will make the warning light go out