Which of the following statements is true concerning carbon dioxide when used as a fire extinguishing agent?

Correct Answer: Option C — Its smothering effect is excellent for class B fires.

Carbon dioxide is an effective extinguishing agent for Class B fires because it displaces oxygen, creating an inert atmosphere that smothers the flames. It is non-conductive and leaves no residue, making it ideal for machinery spaces, though it lacks the cooling capacity of water for deep-seated fires.