A Russian cargo ship with about 30 crew members was in danger of sinking off Russia's eastern coast while bad weather interfered with rescue efforts, state-run Itar-Tass news agency said Friday.
Ice had formed on the outside of the ship and the crew was trying to solve the problem. The crew sent out the signal but there was no explanation of the problem. Because of the bad weather aircraft can' t be used to rescue the crew. According to Itar-Tass the vessel is about 19 miles from the oil rig where rescue vessels are based, while a boat departing from land were still about 4 times farther away.  "The cargo ship had been on route to a fishing area when it experienced problems." The news agency reported, "The ship transfers fish from boats to ports."
The Russian cargo ship was sinking. What was the direct cause?
信息明示题。由The crew sen tout the signal but there was no explanation of the problem．可知，船员虽然发出遇险信号，但是他们没有解释问题的原因，故选A。D的干扰性加大，恶劣的天气阻碍了救援行动，但不是造成沉船的原因。