What does a white rectangular sign indicate?

Answer: A — Regulatory information such as speed limits

A white rectangular sign primarily indicates regulatory information, which includes essential guidelines that drivers must follow. These signs communicate laws or rules that are critical for maintaining order and safety on the road, such as speed limits, no parking zones, and other driving regulations. Following these signs is mandatory, and failure to do so may result in fines or penalties. The signs serve as clear indicators that help regulate traffic flow and ensure the safety of all road users. While other sign colors and shapes convey different types of information—such as warnings or guidance—this specific style focuses on establishing enforceable traffic laws that are crucial for safe driving conditions.