单项选择题
A.Open-bed containers may be used to transport hazardous materials if the cargo is properly secured
B.A portable cargo tank of a flammable，cryogenic liquid may not be in transit for a period exceeding its marked rated holding time unless the liquid is inhibited
C.A portable cargo tank containing a cryogenic liquid must be shipped on deck unless forced ventilation is provided to the tween-decks
D.A container loaded with packages of tear gas would display a placard reading Irritant
单项选择题 You are on a containership carrying a tank container that had been filled with sodium hydroxide solution. The container is empty but has not been cleaned. Which，if any，placard is required?（）.
单项选择题 You are on a containership. The cargo includes a container of small arms ammunition，a container of lead-acid storage batteries and bottles of methyl acetylene. Which statement is TRUE?（）.
单项选择题 You are on a containership. Which statement about the stowage of hazardous materials in containers is TRUE?（）.