What does a red traffic light indicate?

Answer: B — Stop completely

A red traffic light indicates that vehicles must stop completely. This signal is part of the traffic light system designed to manage the flow of traffic at intersections and ensures the safety of all road users, including pedestrians. When the light is red, it is a clear instruction to halt and wait until the light changes to green, which allows for safe movement through the intersection. This strict adherence to stopping at red lights helps prevent collisions and accidents, as it ensures that vehicles are halted before they enter a crossing or intersection where other traffic may have the right to proceed. Observing traffic signals is a fundamental part of safe driving practices and is enforced by law.