Company spokesperson: Household Products magazine claims that our Filterator ... ...

Which one of the following, if true, most seriously undermines the company spokesperson’s argument?
(A) Household Products did not evaluate whether the Filterator X water filter significantly improved the taste of drinking water.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in June 2012 LSAT (PT66): Logical Reasoning B