单项选择题
On a cargo vessel, fire and boat drills must be held within 24 hours of leaving port if the percentage of the crew replaced is more than （）.
A.5% B.10% C.25% D.40%
单项选择题 Which of the listed materials would be considered as a bunting class "C" fire?（）
单项选择题 Except in rare cases, it is impossible to extinguish a shipboard fire by （）.
单项选择题 A class "C" fire is burning （）.
