What is the alarm signal for a fire emergency or fire drill onboard a merchant ship?

Correct Answer: Option A — Continuous blast of the whistle for not less than 10 seconds supplemented by the continuous ringing of the general alarm bells for not less than 10 seconds.

Per 46 CFR requirements, the fire alarm signal consists of a continuous blast of the ship's whistle for at least 10 seconds, supplemented by the continuous ringing of the general alarm bells for the same duration. This standardized signal ensures immediate recognition of a fire emergency by all crew members onboard.