Anthony: It has been established that over 80 percent of those who use

GMATNinja

Can you please address how D is correct?
I rejected D because it states "such reasoning can lead to clearly false conclusions". The clearly false conclusion jumped right at me since Judith doesn't say the conclusion is clearly false. He rather says that conclusion may be true however,... and then goes on to provide reasons.

Hi

Answer option (D) does not state that "the conclusion is clearly false" as you have put it. It states that the "reasoning can lead to clearly false conclusions". In other words, the logic applied to arrive at the conclusion can also be applied to arrive at clearly false conclusions, and hence the logic is flawed.

This is exactly what is happening in the stimulus. Anthony reasons that since a vast majority of heroin users also use marijuana, it proves that "smoking marijuana definitely leads to heroin use". Judith shows that the same logic, that not just a vast majority but every single heroin user also consumes water, and questions (unstated) whether we can conclude that consuming water leads to heroin use. Hence option (D) is the correct answer.

Hope this helps.

Although I marked D, can anyone explain how do we eliminate E ?

(E) calling into question the possibility of ever establishing causal connections solely on the basis of statistical evidence

I think she did not call into question the possibility, she directly reject/weaken Anthony's false conclusion.

(E) calling into question the possibility of ever establishing causal connections solely on the basis of statistical evidence

Notice the word EVER in option E.
Is Judith trying to prove that causal connections can NEVER be established solely on the basis of statistical evidence ? Clearly not!
The use of the word "EVER" renders this option extreme and incorrect.

Why not E?
E: "Calling into question the possibility of ever establishing causal connections solely on the basis of statistical evidence."

This option is broader than Judith's argument. Judith is not questioning all causal connections based on statistical evidence; she is questioning Anthony’s specific reasoning that marijuana leads to heroin use based on his cited statistic. Her argument focuses on the flawed logic in Anthony's reasoning rather than challenging the validity of causal inference as a general principle.

Why not B?
B: "Undermining the credibility of his conclusion by showing that it is a statement from which absurd consequences can be derived."

While Judith points out an absurd consequence (that drinking water could also be linked to heroin use), she doesn’t directly attack Anthony’s conclusion (that marijuana leads to heroin use). Instead, she focuses on the reasoning Anthony uses to arrive at his conclusion. Her point is that Anthony’s line of reasoning is flawed because it could justify absurd conclusions, like water leading to heroin use.

Why D is Correct:
D: "Demonstrating that Anthony's line of reasoning is flawed by showing that such reasoning can lead to clearly false conclusions."

Judith demonstrates the flaw in Anthony’s reasoning by using the water example. She shows that Anthony’s logic (marijuana use precedes heroin use, so marijuana causes heroin use) could lead to the absurd and false conclusion that drinking water causes heroin use. This directly critiques Anthony’s reasoning process, not just his conclusion.