Inspector: The only fingerprints on the premises are those of the owne

The answer is A ,because in the question the officer comes directly to conclusion that someone else wearing gloves might have done the robbery even though there were finger prints of only owner available
Similarly in option A author comes to a conclusion that food they ate is not the cause of illness excluding the option that the very camp cafeteria food that entire staff ate could be the cause of illness(like officer excluding the option of owner could be the thief)

Remaining options doesn't contain flaw similar to the question

Thank you

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In the question stem, we are told fingerprints belong to the owner hence robbery must have been done by a person wearing the gloves.
This implies that the reason/evidence presented in the first line cannot be held responsible and the line presents alternate evidence. There is no connection or a single thread of thought between the two halves.

Now we need to look for answer choices which follow the same pattern -> present one evidence and then present second evidence which tells us how the first piece of evidence is not valid.

A. The campers at Big Lake Camp, all of whom became ill this afternoon, have eaten food only from the camp cafeteria. Therefore, the cause of the illness must not have been something they ate.
--> This presents a similar pattern. We are told they became ill and had food only from the cafeteria. In the second half, we are told that there has to be another reason as they couldn't have taken ill after having food from the cafeteria.

B. The second prototype did not perform as well in inclement weather as did the first prototype. Hence, the production of the second prototype might have deviated from the design followed for the first.
--> Not even close as evidence presented in first half and second half are well connected. Hence incorrect.

C. Each of the swimmers at this meet more often loses than wins. Therefore, it is unlikely that any of them will win.
--> Again the first half and second half are connected. Hence incorrect.

D. All of Marjorie’s cavities are on the left side of her mouth. Hence, she must chew more on the left side than on the right.
--> This one sounds illogical. If she has cavities on the left side, then she should chew from the right side and not the left side. Hence incorrect.

E. All of these tomato plants are twice as big as they were last year. So if we grow peas, they will probably be twice as big as last year’s peas.
--> Again the first half and second half are well connected. Hence incorrect.

The argument in the question assumes that Mr. Tannisch cannot be the culprit. Just because he is the owner does not mean that he could not have hidden it. We have to look for a similar argument that exonerates any individual or entity without giving any justification. Only A meets the criteria. It just ignores camp cafeteria as being the culprit.

hi, please explain how to approach the correct answer. I thought it's D, though not very sure to reason.

This option is logical because she damaged the side which was exposed to more pressure. She was not using the right side of her mouth when chewing, thus, had lower number of cavities there.

The way I reasoned is quite simple, though it could be that it is not the best.

The inspector, if you think about it, concludes something that is totally the opposite of what one would say. If I find fingerprints of a person, it is very likely that this person is involved with the crime.
But he doesn't even take into consideration this fact.

Looking at the answers, the only two that seem plausible are the one you said, and A.
However, your option is misleading because it is IN fact giving the most plausible conclusion which is not what we are looking for. There is no real flaw in the option of the teeth problem, because if I eat with the left side of my mouth it is actually probable that I will find more cavities on that side. It would have been sort of correct if the option said "..then the conclusion is that the person is eating with the opposite side"..or something which you would not expect.

I made too much erroneous question lately maybe mt rerasoning powers have reached saturation i assume maybe some kudous might provide the propulsion required , coming to the question it presents about how the evidence provided support a current conclusion and leads us to think about an alternative the option that standed out was of course the first one jumping in your face..