harsh.champ wrote:The number of people diagnosed with dengue fever (which is contracted from the bite of an infected mosquito) in North India this year is twice the number diagnosed last year. The authorities have concluded that measures to control the mosquito population have failed in this region.

All of the following, if true, would cast doubt on the authorities' conclusion except

Conclusion : Measures to control mosquitoes have failed.

This is a weaken EXCEPT question. So 4 answer choices will weaken the conclusion and 1 answer choice will not.

A. more cases are now reported because of increases in administrative efficiency
Incorrect : This weakens the conclusion by stating that administration has become more efficient and more dengue cases are reported.

B. a very high proportion of the cases were in people who had recently returned from neighboring countries
Incorrect : The number of ppl diagnosed this year is twice the number diagnosed last year because high proportion of cases of dengue fever were in ppl who had returned from neighbouring countries. As such, measures to control mosquitoes have not failed.

C. an effective diagnostic test was introduced about nine months ago
Incorrect : This undermines the conclusion by showing that more ppl were diagnosed this year because the new diagnostic test is more effective.

D. the disease is prevalent only in some industrialized areas which have shown a dramatic increase in population due to migration
Incorrect : Weakens the argument by showing that migration is the reason for increase in dengue cases this year.

E. the incidence (number of cases per thousand) of malaria, also contracted from mosquito bites, has increased
Correct : This supports the conclusion by stating that cases of malaria has also increased hence the authorities have failed to control mosquito population.

harsh.champ wrote:The number of people diagnosed with dengue fever (which is contracted from the bite of an infected mosquito) in North India this year is twice the number diagnosed last year. The authorities have concluded that measures to control the mosquito population have failed in this region.

All of the following, if true, would cast doubt on the authorities' conclusion except

A. more cases are now reported because of increases in administrative efficiency
B. a very high proportion of the cases were in people who had recently returned from neighboring countries
C. an effective diagnostic test was introduced about nine months ago
D. the disease is prevalent only in some industrialized areas which have shown a dramatic increase in population due to migration
E. the incidence (number of cases per thousand) of malaria, also contracted from mosquito bites, has increased