Stop signs are eight-sided and have white letters on a red background.

• A. Four-sided green sign
• B. Circular blue sign
• C. Triangular yellow sign
• D. Eight-sided, red background with white letters

Answer: (D)

Stop signs are meant to be instantly recognizable, so they use a distinctive octagonal shape and a red background with white letters. This combination tells drivers to come to a full stop immediately, even if they can’t read the sign from a distance. The description matching eight sides, a red background, and white lettering is exactly the standard for a stop sign, which is why it’s the best choice.

The other options describe signs that serve different purposes: a four-sided green sign is typically a guide or direction sign, not a stop signal; a circular blue sign usually indicates a required action or information under specific rules; a triangular yellow sign is a warning sign. None of these match the stop sign’s unique octagon shape and color, so they don’t fit the description.