PT29.S1.Q7 - Debbie's magic act

Ashley2018-1

Could someone help me ID what flaw is in the stimulus and why answer choice D is wrong? Is D incorrect because the skeptic is assuming Debbie used another technique aside from the three he was originally testing for? And is the sleight of hand, trick deck, and planted "volunteer" all part of one technique or is it three separate techniques? I'm just confused as to why A is correct if it only mentions one method.
I was thinking D used a trick deck or planted volunteer when the skeptic was testing for slight of hand, then alternated accordingly with the other two tests, but aren't those three separate methods to achieve the same effect?

Admin Note: https://7sage.com/lsat_explanations/lsat-29-section-1-question-07/

canihazJD

LSAT Prep Test 31 Section 1, #7 Magic

31.1.7 is a logic game?

Edit: found it 29.1.7

They did three trials, each controlling for one way Debbie might accomplish the trick, then concluded that she's using none of those three methods. But she could have used any of those methods, just not the one the particular trial was eliminating.

I controlled for condition A in trial 1, B in trial 2 and C in trial 3. Therefore in all of trials 1, 2, and 3; neither A, B, or C took place. We don't know this. We only know that in trial 1, A didn't happen (but B and C are possible), and so on for trial 2 and 3.

In other words, in the first trial (videotaped) no sleight of hand was found. How do you know she didn't use a trick deck or planted volunteer?

D is both descriptively inaccurate and not the flaw identified above. We don't know what the skeptic considered or didn't... just what he tested for.

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D is irrelevant since the conclusion said none of the 3 techniques were used. Who cares about the possibilities that she was using something else. And if she indeed used a technique other than the 3 mentioned, the conclusion still holds true.