Final answer:
In the metric system, road speed is most commonly measured in kilometers per hour. (option C)
Step-by-step explanation:
In the metric system, road speed is measured in kilometers per hour (km/h). This unit of measurement reflects the distance traveled in kilometers over one hour. The use of kilometers per hour is standard practice globally in countries that adhere to the metric system. This standardization facilitates consistency in expressing and comprehending vehicle speeds, contributing to international road safety standards and efficient communication.
The choice of kilometers as the primary unit aligns with the metric system's emphasis on powers of ten and logical unit conversions. It offers a straightforward representation of distance in a base-ten system, simplifying calculations and comparisons. This uniformity aids in international cooperation and trade, as road speed limits, traffic regulations, and vehicle specifications are communicated consistently across borders.
This practice promotes effective communication and contributes to a safer and more organized global transportation system.