[讨论]一道题目

Roland: The alarming fact is that 90 percent of the people in this country now report that they know someone who is unemployed.

Sharon: But a normal, moderate level of unemployment is 5 percent, with 1 out of 20 workers unemployed. So at any given time if a person knows approximately 50 workers, 1 or more will very likely be unemployed.

Sharon's argument relies on the assumption that  

(A) normal levels of unemployment are rarely exceeded
(B) unemployment is not normally concentrated in geographically isolated segments of the population
(C) the number of people who each know someone who is unemployed is always higher than 90% of the population
(D) Roland is not consciously distorting the statistics he presents
(E) knowledge that a personal acquaintance is unemployed generates more fear of losing one's job than does knowledge of unemployment statistice

答案是B。这应该是道加强题，但是我实在看不出来B和结论之间有什么联系。哪位大侠指点一二？

P.S，这是新东方出的那套教材里的SECTION 14第16题，我也不知道该怎么标号。

I thought B means unemployment is distributed evenly in the country, so that 1 out of 50 is unemployed.

When you read what Sharon says, you can get that assumption.

It's only a way of twisting the structure of a sentence to hide the meaning.

B的意思就是说: 失业不可以只集中在一块地方而其他地方没有.

反过来说: 如果一个国家有50个区, 但只有一个区才有人失业, 那么sharon的一番话就不能成立了.