Plumb-Ace advertises that its plumbers are more qualified than plumbers at any other major plumbing firm in the region because Plumb-Ace plumbers must complete a very difficult certification process. Plumb-Ace plumbers may or may not be more qualified, but clearly the certification process is not very difficult, because nearly everyone who takes the written portion of the certification exam passes it very easily. The reasoning in the argument is flawed in that it ['takes for granted that plumbers are not qualified unless they complete some certification process', 'presumes that since one part of a whole lacks a certain characteristic, the whole must lack that characteristic as well', "overlooks the possibility that plumbers at other firms in the region complete certification processes that are even easier than that completed by Plumb-Ace's plumbers", 'infers that a claim is false on the grounds that an inadequate argument has been given for that claim']