What does it mean if a sign is rectangular?

Answer: B — It indicates regulatory information.

A rectangular sign primarily indicates regulatory information. These signs are designed to convey important rules and regulations that drivers must follow to ensure safety and compliance with traffic laws. For instance, you might see speed limit signs, yield signs, or no parking signs presented in a rectangular format, clearly indicating what is required or prohibited in that area. The other types of signs, such as warning signs that are typically diamond-shaped, or caution signs that may be circular or other shapes, serve different purposes. However, when encountering a rectangular sign, it is crucial to interpret its message as a directive that informs drivers of their legal obligations on the road.