How is the speed limit indicated on the road?

Answer: B — Through road signs placed at appropriate intervals

The speed limit is indicated on the road primarily through road signs placed at appropriate intervals. This is essential for ensuring that drivers are aware of the maximum speed they should adhere to in various areas, such as residential zones, highways, or construction sites. Road signs provide clear, visual communication of the speed limit, helping maintain safety and order on the roads. Driver awareness of speed limits is critical for preventing accidents and promoting traffic flow. Other methods, such as technology in vehicles or verbal announcements, are not standard practices for indicating speed limits on public roads and can create confusion or reliance on devices instead of direct observation of road safety signs. Thus, the placement of signs is the most effective and universally understood method for conveying speed limits to drivers.