What type of sign primarily communicates regulations that must be followed?

Answer: C — Regulatory sign

Regulatory signs play a crucial role in traffic management as they are designed to inform motorists of specific laws and regulations that must be adhered to while driving. These signs indicate mandatory actions that affect driver behavior, such as speed limits, yield requirements, and no entry instructions. Their primary purpose is to ensure safety and compliance on the road by conveying clear, enforceable rules. In contrast, warning signs alert drivers to potential hazards or changes in road conditions, guidance signs provide directional and informational assistance, and information signs convey general information unrelated to regulations. Therefore, regulatory signs stand out as the key elements that directly communicate rules that drivers are obligated to follow in order to maintain safety and order on the roads.