Official Solution:
In 85 percent of the bacterial contamination incidents recorded at artisan cheese aging facilities last year, one or another of a group consisting of only 14 percent of the world's artisan aging facilities was involved. Since the other 86 percent of facilities generally use the same types of cave ventilation and temperature-control systems as these high-contamination facilities, significant differences in aging and handling practices must have been responsible for the disparity.
Which of the following, if true about artisan cheese aging facilities last year, most seriously weakens the argument above?
A. The 14 percent of facilities with the most contamination incidents collectively aged a greater total volume of cheese than any other comparable-sized group of facilities.
B. Regional food safety inspectors issued far more hygiene citations to the high-contamination facilities than to the other facilities last year.
C. Twelve percent of the facilities accounted for 93 percent of all cheese aged globally last year, and those facilities were involved in 76 percent of the contamination incidents.
D. The average duration of the cheese-aging process across the 14 percent of facilities was nearly double the global median for artisan cheese production.
E. The 14 percent of facilities experienced a 100 percent increase in their total production capacity over the previous fiscal year.
The argument eliminates equipment as a cause of the disparity - the 86 percent of facilities with lower contamination rates use the same ventilation and temperature-control systems - and concludes that aging and handling practices must explain why 14 percent of facilities were involved in 85 percent of contamination incidents. To weaken the argument, the correct answer must offer an alternative explanation for the raw count disparity.
(A) Incorrect. This is the key trap. It introduces volume as a potential alternative cause - if the 14 percent aged more cheese, more contamination incidents would be expected. However, knowing they aged more than any other comparable-sized group does not establish what fraction of global cheese aging they represent. Without that figure, there is no way to determine whether their volume of aging actually accounts for 85 percent of incidents. The argument cannot be undermined by a volume claim that is too vague to be compared against the incident proportion.
(B) Incorrect. More hygiene citations at the high-contamination facilities indicate that inspectors identified more hygiene-related violations there - confirming that practices at those facilities differed from those of other facilities. This supports the argument's conclusion rather than undermining it.
(C) Correct. If 12 percent of facilities - corresponding to the high-contamination group - handled 93 percent of all cheese aged globally last year, then their disproportionate share of contamination incidents is explained by their vastly greater exposure, not by inferior practices. Notably, being involved in only 76 percent of incidents while accounting for 93 percent of all aging means their per-unit contamination rate was actually below the global average. The raw count disparity the argument relies on is therefore a product of volume, not of deficient practices, and the conclusion does not follow.
(D) Incorrect. Aging duration is itself an aging practice - it falls squarely within the "aging and handling practices" the argument identifies as the cause of the disparity. If the high-contamination facilities age cheese for nearly twice as long as the global median, that confirms a practice difference between the two groups, which supports the conclusion rather than undermining it.
(E) Incorrect. A doubling of production capacity does not establish that these facilities actually produced twice as much cheese during the relevant period, nor does it indicate what share of global cheese aging they represent. Even if capacity was fully utilized, we would still need to know their fraction of global aging output relative to their fraction of contamination incidents to determine whether volume explains the disparity. This choice provides insufficient information to undermine the conclusion.
Answer: C