What does a flashing red light mean?

Answer: C — Come to a complete stop, then proceed when safe

A flashing red light indicates that drivers must come to a complete stop before proceeding. This is similar to the requirement at a stop sign, as it serves to alert drivers to a potential hazard or situation that requires their attention. After stopping, the driver can proceed only when it is safe to do so. This rule is critical for ensuring safety at intersections or areas where traffic may be unpredictable, allowing for better judgment before continuing. In contrast, the other options do not adequately represent the meaning of a flashing red light. Proceeding with caution does not emphasize the necessity of a complete stop, while yielding to all traffic implies a reduction in vigilance to potential dangers. Activating hazard lights serves a different purpose, primarily signaling to other drivers of an issue rather than dictating immediate actions at a traffic signal.