A solid blue circle safety sign indicates which type of sign?

• A. A warning sign
• B. A mandatory sign
• C. An informational sign
• D. A prohibition sign

Answer: (B)

A solid blue circle signals a mandatory instruction. The blue color shows that action is required, and the circular shape reinforces that it’s something you must do rather than just a warning or a prohibition. For example, a blue circle with a helmet symbol means wearing a hard hat is required in that area. This differs from warning signs (typically yellow triangles), prohibition signs (red circles with a slash), and informational signs (blue panels that convey information or directions). So the solid blue circle is a mandatory sign.