What does a red traffic light mean?

Answer: B — Stop completely and do not proceed

A red traffic light means that drivers must stop completely and may not proceed until the light turns green. This signal is crucial for maintaining safe traffic flow and preventing accidents at intersections. When you observe a red light, it indicates that cross traffic may be moving, so stopping completely ensures that you have adequate time to assess the situation before proceeding. This rule is in place for the safety of all road users, including pedestrians, who often have the right of way when crossing at intersections with a red light in effect. In contrast, options related to proceeding or yielding would lead to potentially dangerous situations, as they do not align with the primary purpose of a red light, which is to signal a complete halt. Similarly, slowing down to prepare to stop might not provide sufficient response time in scenarios where immediate stopping is necessary.