What indicates a no parking zone?

A no parking zone is clearly indicated through a combination of specific signs, colored curbs, and markings on the road. Signs are placed to explicitly inform drivers that parking is prohibited in that area, providing clarity about the restrictions and often including information about the times when the restrictions apply. Colored curbs, such as red or yellow, signal important parking information as well; for example, a red curb typically indicates that no parking is allowed, while a yellow curb can indicate loading zones or temporary restrictions.

Markings on the pavement may further delineate the no parking area, such as words painted on the street (e.g., "No Parking") or symbols that indicate the parking rules. All these elements work together to ensure that drivers are aware of where parking is not permitted, enhancing safety and compliance with traffic regulations. This comprehensive approach is what makes option C the most accurate answer.