Final answer:
Regulatory signs represent laws (option B), which must be followed by road users. They indicate traffic regulations such as speed limits or stop requirements, playing a role in maintaining road safety and order.
Step-by-step explanation:
Regulatory signs are crucial in providing instructions to road users, and they play a key role in maintaining order and safety on the roads. The correct answer to the student's question is that regulatory signs represent laws, meaning option B is correct. To further clarify, these signs are designed to inform road users of traffic laws and regulations that must be obeyed. For example, stop signs, yield signs, and speed limit signs are all regulatory signs that convey legal requirements. Ignoring these could lead to traffic violations or accidents. Additionally, regulatory signs can act as informal trade barriers when safety and environmental standards are involved, affecting how businesses operate within different regions.