A blue curb indicates parking spaces reserved exclusively for disabled persons with a special placard or license plate.
The question, "A blue curb means" refers to regulations for parking zones indicated by colored curbs, which is a topic related to traffic laws and regulations. The correct answer to this question is: B) Parking for disabled persons with a special placard or license plate. This means that parking spaces next to a blue curb are designated specifically for vehicles that have a valid disabled person parking placard or disabled person or disabled veteran license plates.