进来讨论一下，这题有好几个版本，我的版本目前还没有被讨论过

夜黑风高

正确答案应该是C  ManhattanGMAT 的官方解释 说得很好 可以细致体味一下这个思路

The first step to correctly strengthening or weaking a CR argument is to properly identify the conclusion. In this case the conclusion is easily identifiable due to the indicator word "therefore." Thus, the conclusion is the entire final sentence. To strengthen this conclusion, we must support the contention that the number of people contracting Lyme disease would actually decline by increasing the population of other species on which the larvae of deer ticks feed. Use a Strengthen/Weaken Slash Chart to assess each answer choice individually.

A. Ticks do not suffer any adverse consequences from carrying the bacterium that
causes Lyme disease in humans.
-Irrelevant. The conclusion is about the number of humans that contract Lyme Disease

B. There are no known cases of a human’s contracting Lyme disease through contact
with white-footed mice.
-Irrelevant. The argument never suggests that the mice can directly infect humans.

C. A deer tick feeds only once while in the larval stage.
-Strengthen. If the larvae of a deer tick only feeds once and there are more potential uncontaminated food sources for the larvae, this supports the contention that fewer ticks would acquire the bacterium and thus infect fewer humans.

D. A single host animal can be the source of bacteria for many tick larvae.
-Weaken/Irrelevant. If anything, this answer choice suggests that multiple deer ticks can acquire the bacteria from one mouse. This definitely does not strengthen that FEWER humans would be infected.

E. None of the other species on which deer tick larvae feed harbor other bacteria that
ticks transmit to humans.
-Irrelevant. This answer choice is outside the scope of the argument. The conclusion is specifically about Lyme Disease rather than "other bacteria".

The credited response is C