Which option is NOT part of the warning sign described?

• A. Warning
• B. Dangerous cargo
• C. No visitors
• D. Keep doors locked

Answer: (D)

A warning sign communicates a hazard and any immediate access restrictions related to that hazard. It typically starts with the word “Warning” and then specifies what the danger is, and may note that visitors are restricted if needed. The phrase “Keep doors locked” does not describe a hazard or a specific access restriction due to danger; it’s an instruction about security or containment procedures rather than a hazard warning. On the other hand, “Warning” signals that there is a risk, “Dangerous cargo” identifies what the risk involves, and “No visitors” states a direct access restriction tied to safety. So the statement about keeping doors locked doesn’t fit the nature of a warning sign and is the best choice as not part of the described warning sign.