Dr A is performing what is known as an Informal Logical Fallacy nicknamed “Begging the Question.”
Basically this occurs when the author’s Premises aren’t used as support for the Conclusion: the argument’s premises already assume that the conclusion is true.
The author has already assumed the truth of his conclusion, rather than providing any support for the conclusion.
“Running helps you lose weight because running leads to weight loss.”
In the above example, there is no support for the claim that running helps you lose weight. The conclusion is already assumed in the premises.
The above is a more extreme example but it basically occurs when the facts that are used as support already assume that the conclusion is true.
Dr A says: “the studies must have been faulty because the vaccine is worthless.
Dr A is out to prove that the studies proving that the vaccine might have some value must be wrong because the vaccines does not have any value.
That is essentially the pattern we are looking for.
(B) There is support offered in the argument pattern in B. Because the author doesn’t trust Jerrold Jersey’s milk recommendations, the author won’t buy the milk.
This is a separate logical fallacy in which you dismiss someone’s argument because of something personal about the author: not on the basis of the facts presented.
It does not fallow the same pattern.
(C) “Wingzz tennis balls perform the best because they are far more effective than any other.”
Just as Dr. A did in his argument, this author is already assuming the Conclusion within the premises.
Effectively, because the balls are the most effective ———-> they are better than any other ball.
There is a slim opening to say “what does effective really mean.” Maybe the ball’s effectiveness is some kind of industry jargon that somehow indicates the balls are better and it can be relied on as actual evidence.
However, common sense would tell us that the author is basically repeating the conclusion in his premises, just as Dr A did in the passage.
I believe this answer best illustrates the “Begging the Question” fallacy.
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