Best answer: (B)
Identify the conclusion and the premise(s):
Premise: It is sometimes thought that pollution and exposure to large numbers of people make urban living unhealthy.
Premise: Over the last half-century, the deer population in the United States has grown.
Premise: Over the last half-century, Americans have moved out of cities, in fact further and further outward into suburbs.
Premise: The closer contact with deer has exposed Americans to Lyme disease as never before.
Explanations:
Identify question type and give some tips:
The answer will not be too far off from the conclusion, but keep in mind what we know: Lyme disease was a less significant problem in the United States fifty years ago, when Americans less in suburbs than they do today and thus had less contact with deer. For this passage, contact with deer is clearly correlated with exposure to Lyme disease. We have not, however, said anything definitive about urbanites today.
Scan each answer choice by eliminating progressively each “wrong” answer to finish with the “best” answer:
It may well be the case that the newly infected suburbanites have now exposed their urban compatriots to Lyme disease, so (A) is not necessarily true. (C) is outside the scope of the question. (D) and (E) are unfounded; we have not compared the general health risks of the two. (B) is correct; the passage makes clear that some suburbanites have dwelt in cities and that they did not always face such rampant exposure to Lyme disease.