14. Herbalist: Many of my customers find that their physical coordination improves after drinking juice containing certain herbs. A few doctors assert that the herbs are potentially harmful, but doctors are always trying to maintain a monopoly over medical therapies. So there is no reason not to try my herb juice.
The reasoning in the herbalist’s argument is flawed because the argument
(A) attempts to force acceptance of a claim by inducing fear of the consequences of rejecting that claim
(B) bases a conclusion on claims that are inconsistent with each other
(C) rejects a claim by attacking the proponents of the claim rather than addressing the claim itself
(D) relies on evidence presented in terms that presuppose the truth of the claim for which the evidence is offered.
(E) mistakes the observation that one thing happens after another for proof that the second thing is the result of the first
Which one of the following is an assumption required by the argument?