Which of the listed methods is the most effective to fight a fire on the open deck of a vessel if using a dry chemical type fire extinguisher?

Correct Answer: Option D — All of the above.

Effective dry chemical firefighting requires a tactical approach: attacking from the windward side to prevent smoke inhalation, aiming at the base of the flames to interrupt the chemical chain reaction, and using a rapid sweeping motion to cover the entire fuel surface area for complete extinguishment.