Wrong flaw. Like the stimulus, this argument attempts to cast doubt on evidence that has been used to support a universal belief in the falseness of a claim (in this case, said doubt comes from a lack of citations). Unlike the stimulus, however, (A) concludes that it is “quite likely” that the refuted claim is true; the stimulus only goes so far as to conclude that the refuted claim is “more plausible” than previously thought.

Wrong flaw. The support for the conclusion is insufficient: we only know that most botanists believe the species are the same, and that some of the botanists who disagree aren’t very well educated on the subject. The argument doesn’t eliminate the possibility that the majority of botanists are wrong! This isn’t the same flaw we see in the stimulus, though, which determines that a claim is plausible merely because the support for one argument against that claim is flawed.

This argument starts by stating that a belief (aluminum being as good a frame material as titanium) has been rejected. It then adds that a new source has provided an argument against that belief, but the argument is flawed. Because the new argument against the belief is flawed, (C) concludes that the belief must be more plausible than previously thought. This commits the same lack of support vs. false conclusion flaw, because the validity of one argument against a claim means nothing about the validity of the claim itself.

Wrong flaw. This argument attempts to use information about wine’s age to support a claim about wine’s quality without giving any information about how age corresponds with quality. That isn’t the same flaw as the one in the stimulus, which determines that a claim is plausible merely because the support for an argument against that claim is flawed.

Wrong flaw. This points out a factor that researchers have not considered in their studies and concludes that the unstudied question will yield a specific result (too much TV impairs development). This isn’t a valid argument, because there’s no evidence that a more comprehensive study would yield the results the author anticipates. But it doesn’t commit the flaw from the stimulus, which determines that a claim is plausible merely because the support for an argument against that claim is flawed.