Mr. Klemke argues that the complaints recently lodged against his roofing company are unfounded, on the grounds that ...

I understand why answer choice C is out because the person who is offering the argument isn't biased. There is no indication of that in the stimulus. However, can't the argument be made that it is relying on a sample of opinions since the stimulus says, "the complaints recently lodged against his roofing company are unfounded on the grounds that each of the complainants disagrees with Klemke's widely known political views." Aren't the complaints a sample of opinions? I see where "B" is a good answer choice but "D" is tempting too.