A flashing red traffic signal at an intersection means which of the following?

Answer: D — Neither A nor B.

A flashing red traffic signal at an intersection indicates that drivers must come to a complete stop, just as they would for a stop sign. After stopping, drivers can proceed only when it’s safe to do so, which may include yielding the right-of-way to other vehicles and pedestrians as necessary. The requirement to stop makes options that suggest only slowing down (as in the first choice) or stopping only when necessary (as in the second choice) incorrect. Thus, the understanding of the flashing red light is that it commands a definite stop before proceeding safely, making the correct interpretation align with a strict adherence to traffic rules at such signals.