What is the color of a stop sign?

Answer: A — Red

A stop sign is always red because red is a universal color that signifies danger, warning, and stop. Blue, green, or gray would not be suitable colors for a stop sign because they do not convey the same message or meaning as red. These colors may also be used for other traffic signs that are not necessarily related to stopping. Therefore, red is the appropriate and expected color for a stop sign.