Yeah good question. There is another more difficult version of same question (evaluate argument) ,which derailed me completely (took 6 mins to ans -and incorrectly ).

For this one - argument is : 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
This is strengthened if we can show that by increasing number of these species would help in less people contracting lyme

Choice C gives a case - if the deer tick feeds only once in larval stage (which is the stage when it picks up bacterium) and feeds on 'other species' which are not infected, clealy it will not pick bacterium and fewer people would contract lyme (people contract only from deer picks).

Ans C it is.
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Most important component: Cast you vote

Yes, it takes a min to understand the relation:

Bacteria -> whitefooted mice -> larvae of deer ticks -> humans

Larvae feed on other species which do not harbor the bacterium so increase their population. Fewer people will get Lyme disease.

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

Out of scope.

B. There are no known cases of a human’s contracting Lyme disease through contact
with white-footed mice.

Out of scope. Argument doesn't discuss whether humans can directly contract Lyme disease. The argument only deals with Lyme disease through deer ticks.

C. A deer tick feeds only once while in the larval stage.
If there are more uninfected food sources, it is likely that when the larvae feed, they feed on uninfected food. If the larvae do not feed again, it is probable that they will not carry the bacterium of Lyme disease and hence fewer humans will get affected. Answer (C)

D. A single host animal can be the source of bacteria for many tick larvae.
It doesn't strengthen our plan since bacteria could still proliferate if a single host can be source for many tick larvae. So we may not see much decrease in Lyme disease in humans.

E. None of the other species on which deer tick larvae feed harbor other bacteria that
ticks transmit to humans.

Out of scope.
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Karishma
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