[求助]OG2017-CR-647加强题排它因的困惑

茄子要加油

Between 1980 and 2000 the sea otter population of the Aleutian Islands declined precipitously. There were no signs of disease or malnutrition, so there was probably an increase in the number of otters being eaten by predators. Orcas will eat otters when seals, their normal prey, are unavailable, and the Aleutian Islands seal population declined dramatically in the 1980s. Therefore, orcas were most likely the immediate cause of the otter population decline.

Which of the following, if true, most strengthens the argument?
A、The population of sea urchins, the main food of sea otters, has increased since the sea otter population declined.
B、Seals do not eat sea otters, nor do they compete with sea otters for food.
C、Most of the surviving sea otters live in a bay that is inaccessible to orcas.
D、The population of orcas in the Aleutian Islands has declined since the 1980s.
E、An increase in commercial fishing near the Aleutian Islands in the 1980s caused a slight decline in the population of the fish that seals use for food.

提炼出来的逻辑链如下：
Fact：Orcas没有seal吃的情况下会吃otter，seal确实少了
P：1980-2000 otter数量下降了
C：otter下降很可能是被orcas吃了

可以理解答案C。
想额外求证下选项B，是否是排除它因（otter被seal吃掉了），选项B是否可以增加一点点可能性，只是没有选项C most strengthens？谢谢

茄子要加油

幻北 发表于 2017-2-5 18:44
辅导班老师？这么不负责任

是呢，但是大家也都认可的样子，不知道是真的认可还是没多想呢

茄子要加油

幻北 发表于 2017-2-5 16:39
CR各有各法，每个理解不同，我说说我对于B的看法，我觉得B是挖了一个坑，引导我们往加强想。原文的逻辑关系 ...

谢谢解答，我就是被老师直接甩出一句无关给困惑了，看了你的分析很清楚了