What does a flashing yellow light indicate?

Answer: C — Proceed with caution

A flashing yellow light signals to drivers that they should proceed with caution. It serves as a warning that there may be an unusual condition ahead, such as a pedestrian crossing, a school zone, or an intersection that requires drivers to be alert. The intention is not to stop unless necessary but rather to be prepared for potential hazards. This distinction is crucial for maintaining safety on the road, as it encourages drivers to slow down and be vigilant without coming to a complete stop unless the situation dictates that action. The other options reflect misunderstandings of traffic signals. Stopping immediately is not required; instead, caution is advised. Speeding up could lead to dangerous situations where a driver isn't prepared for obstacles or changing conditions. Yielding to all traffic is also misleading because while vigilance is essential when encountering other vehicles or pedestrians, drivers do not have to yield unless it is explicitly indicated by other traffic signs or signals.