给了答案也没看懂，有人指点下么？？ 谢谢啦

Lyme disease is caused by a bacterium transmitted to humans by deer ticks.  Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected white-footed mice.  However, certain other species on which the larvae feed do not harbor the bacterium.  Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium―and hence the number of people contracting Lyme disease—would likely decline.

Which of the following, if true, most strengthens the argument?

1. Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.

2. There are no known cases of a human’s contracting Lyme disease through contact with white-footed mice.
3. A deer tick feeds only once while in the larval stage.

4. A single host animal can be the source of bacteria for many tick larvae.
5. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

这个题怎么读也没怎么读明白 看了答案还觉得不可理解...我哭死了 怎么就这么难呢

答案是C

我觉得是选C啊

题目的意思是说deer ticks 在larval stage 吃的是infected white-footed mice，但是other species 的食物就没有infected bacterium。结论：如果other species多的话那deer ticks感染细菌的就会少一些。问 strengthens 的。

C：如果deer tick 在 the larval stage.只吃一次。就是说只吃一次，随着other species的增多那吃的是other species，就排除了吃infected white-footed mice的情况，所以感染的就会越来越少。 

不知道说清楚没