What must you do at a flashing red signal at an intersection?

Answer: B — Stop completely before proceeding

At a flashing red signal at an intersection, you must stop completely before proceeding. This is because a flashing red signal indicates that the driver must come to a complete stop and then proceed with caution. Options A, C, and D are incorrect because they either do not require a complete stop or do not take into account the possibility of having to yield to other vehicles or pedestrians. It is important to follow the traffic signals and signals at intersections to ensure the safety of all road users.