You're on a motorway. What do the speed-limit signs inside a red circle indicate? You're on a motorway. What do the speed-limit signs inside a red circle indicate?

• Possible answers:

   
• A. The speed limit on the sign is advisory
• B. The national speed limit will always apply
• C. The speed limit is always 30 mph
• D. The speed limit on the sign must be obeyed