What does a red light signify?

Answer: B — Stop

A red light signifies stop. This is because traffic lights use a system of colors to regulate traffic flow, with each color representing a different action for drivers to take. Red is typically considered the color of danger and is used to signal drivers to come to a complete stop. Option A, yield, is incorrect because this is represented by a yellow light. Option C, go, and option D, slow down, are also incorrect as they represent the actions drivers should take when seeing a green and yellow light respectively.