A、because they cleaned the ship with lethal liquid. B、as a result of loading poisonous ores. C、as a result of too much exposure

Investigators yesterday were trying to determine the source of a lethal gas in Malaysia that killed five Chinese cargo ship crewmen and injured one on Tuesday. The six men inhaled poisonous gas while cleaning a cargo ship during a Malaysian stopover. The ship was bound for Thailand with load of ore.
   The deceased, who ranged in age from 23 to 42, were from East China’s Shanghai and Jiangsu provinces.
   The survivor, 23-year-old Lin Dexiang, is being treated in a local hospital near the accident site, the Kuantan port of Pahang state, about 300 kilometers east of the Malaysian capital of Kuala Lumpur.
   Two officials from the Chinese Embassy have been watching the investigation and visited the scene. The source of the poison remained unclear yesterday.