单项选择题
A.power ventilation B.gooseneck vents and flame screens C.at least two ducts extending to the weather deck D.a vent header system
A.gooseneck vents and flame screens B.pressure-vacuum relief valves C.branch vent lines and a vent header D.forced draft blowers
A.cofferdams B.gastight bulkheads C.passageways or living quarters D.general cargo spaces