The source for this question is internet(bestsamplequestions.com)

Neighboring landholders: Air pollution from the giant aluminum refinery that has been built next to our land is killing our plants.

Company spokesperson: The refinery is not to blame, since our study shows that the damage is due to insects and fungi.

Which of the following, if true, most seriously weakens the conclusion drawn by the company spokesperson?

a) The study did not measure the quantity of pollutants emitted into the surrounding air by the aluminum refinery.

b) The neighboring landholders have made no change in the way they take care of their plants.

c) Air pollution from the refinery has changed the chemical balance in the plants' environment, allowing the harmful insects and fungi to thrive.

d) Pollutants that are invisible and odorless are emitted into the surrounding air by the refinery.

e) The various species of insects and fungi mentioned in the study have been occasionally found in the locality during the past hundred years.

Can someone please comment on the correct answer. i'll disclose OA afterwards.

Answer should be (C)

GMAT 2007

Answer should be C

Thanks! I guessed C too. but somehow given OA is B. i guess that is wrong then. i just wanted to have a second eye on the question.

The correct answer must WEAKEN the conclusion that the refinery is NOT to blame for the damage to plants. Answer choice C is the only one that shows that the refinery IS to blame.

All ya'll are correct: C is the best answer.

-dan