各位大NN，帮我解答下这个逻辑题目GDW-11-Q24

fiona8828

Each year red-winged blackbirds stop in a certain region of Midland
                    Province on their spring and fall migration. In the fall, they eat a significant portion of the province’s sunflower crop. This year Midland farmers sought permits to set out small amounts of poisoned rice during the blackbirds’ spring stop in order to reduce the fall blackbird population. Some residents voiced concern that the rice could threaten certain species of rare migratory birds. Nevertheless, the wildlife agency approved the permits.

1. In the region where the red-winged blackbirds stop, they are the first birds to be present in the spring.

2. The poison that farmers want to use does not kill birds but rather make them incapable of producing viable eggs.

3. Since rice is not raised in midland province, few species of birds native to the province normally eat rice.

4. Without the permit, any farmers shown to have set out poison for the blackbirds would be heavily fined

5. The poison that farmers got approval to use has no taste or smell that would make it detectable by birds.

正确答案是A，但是我怎么也想不通呢？

我选的是B

去站内搜索也没有找到这个题目。

各位好心的NN帮我解答下吧

gaoliang641

如果对别的物种的鸟类也有威胁，哪么一定是因为别的物种的鸟类也可能吃到这种有毒的大米。 哪么如果削弱这个结论，有两种可能

1.  只有红衣黑鸟能吃到这种有毒大米，别的鸟吃不到

2. 红衣黑鸟和别的鸟都可以吃到，但有毒的大米对别的鸟不构成危害。 

B肯定不对，因为不下蛋指的是对所有的鸟类，而没有强调只对红衣黑鸟。 

A对是因为满足了第一可能。 如果红衣黑鸟是第一批来的候鸟，哪么他们就先吃有毒的大米。这样，别的鸟就吃不到。 

当然，我们也可以钻牛角尖，说有毒的大米万一红衣黑鸟吃不完，留下来了给别的鸟吃了怎么办？但BCDE以上两种可能都不满足。所以A还好一点。 

fiona8828

 哦 我懂了 你解释的很好啊 恩恩 受益匪浅。谢谢谢谢啊