Drawings of your ship indicate the use of "B" class bulkheads. The "B" indicates which of the following?

Correct Answer: Option B — "B" class bulkheads must not allow flame passage for 30 minutes when subjected to a fire test.

Under 46 CFR 72.05, 'B' class bulkheads are fire-rated divisions designed to contain fire within accommodation spaces. These bulkheads must withstand standard fire tests for 30 minutes without allowing the passage of flame, ensuring structural integrity and safety for crew during the initial stages of a fire.