Premise : The shop originally placed the advertisement in order to increase business, but found that the majority of its sales are made to those who do not read the publication.
Conclusion: Canceling the advertisement in that publication will save the shop's money.

This is an EVALUATE the argument + EXCEPT problem. The correct choice would NOT help in evaluating the argument.

Let's look at the choices.

(A) How does the cost of the advertisement compare to the profit from purchases made by those who have responded to it?
If the cost of the advertisement is lesser then the profit from the purchases made by the responders of the advertisement, cancelling the advertisement is not a good idea even if the majority of the customers are not the readers. Thus, this choice helps in making decision.
(B) Are there other trade publications that attract the shop's typical clientele in which an advertisement would be likely to reach prospective customers at the same cost?
If there are other trade publications that attract shop's typical clientele, it's a good idea to cancel the advertisement in the current publication and switch to those publications.Thus, this choice helps in making decision.
(C) Is a significant proportion of the shop's competitors satisfied with the effect of their advertisements in trade publications?
The competitors are satisfied. So what? Their satisfaction will not boost the shop's sales.
Moreover, are they advertising in the same publication? We can't infer. So, this choice is not helping in anything on making the decision.
(D) How many buyers who responded to the advertisement were professional antique dealers who generally make relatively expensive purchases?
To the shop what exactly matters is the money it makes from the advertisement and not the actual count of people who respond to the advertisement. If there are many responders who make relatively expensive purchases, it's wise to continue with the publication for the advertisement.
(E) Is any significant change expected in the pattern of the trade publication's circulation?
If the current publication is likely to change its circulation, we may expect that the changed circulation will include who make actual sales. In such case, it's good to stay with the current publication for the advertisement and wait for sometime. Thus, this choice helps in making decision.

C

Conclusion: The shop is considering canceling the advertisement in that publication in order to save money.

Prethinking: Saving money is the objective. To get least relevant, the choice doesn't help in saving money for the sale, will be our answer.

The answer to which of the following questions would be LEAST relevant to the shop's decision?

(A) How does the cost of the advertisement compare to the profit from purchases made by those who have responded to it? -> cost and profit is required to compare to decide, if the shop follow the conclusion or not. It is relevant.

(B) Are there other trade publications that attract the shop's typical clientele in which an advertisement would be likely to reach prospective customers at the same cost? -> Okay. May be publications can attract few customers, we need to know. It is relevant.

(C) Is a significant proportion of the shop's competitors satisfied with the effect of their advertisements in trade publications? -> Shops' competitors are satisfied or not, it is not our goal. Irrelevant.

(D) How many buyers who responded to the advertisement were professional antique dealers who generally make relatively expensive purchases? -> It makes sense to evaluate. relevant.

(E) Is any significant change expected in the pattern of the trade publication's circulation? -> Yes! The shop must be knowing it, else his decision to stop publications may backfire his/her decision.

So, I think C.

IMO C

An antique and curiosity shop is weighing the advantages of renewing its regular advertisement in a monthly trade publication. The shop originally placed the advertisement in order to increase business, but found that the majority of its sales are made to those who do not read the publication and have not seen the ad. The shop is considering canceling the advertisement in that publication in order to save money.

The answer to which of the following questions would be LEAST relevant to the shop's decision?
Crux:
Shop is weighing advantages of renewing the ad since it found that majority of its sales are really not the ones after reading the ad.
Hence, they are considering canceling the ad.

Now,in order to assess the situation, we can have many scenarios. Some +ve/-ve below :
1. What if the folks reading the ad spread this by word of mouth and new customers are added that way?
2. What if the ad was not giving good results to everyone and it wasn't really the shop's fault?
3. What if the cost of the ad is negligible when compared to the profits earned by the shop?

Pre thinking on the above lines, let us see the options.


(A) How does the cost of the advertisement compare to the profit from purchases made by those who have responded to it?
Useful: As stated above.

(B) Are there other trade publications that attract the shop's typical clientele in which an advertisement would be likely to reach prospective customers at the same cost?
Useful: As stated above.

(C) Is a significant proportion of the shop's competitors satisfied with the effect of their advertisements in trade publications?
Least useful- The above factor may not contribute to the decision.

(D) How many buyers who responded to the advertisement were professional antique dealers who generally make relatively expensive purchases?
Useful.

(E) Is any significant change expected in the pattern of the trade publication's circulation?
Useful: As stated above.

KAPLAN OFFICIAL EXPLANATION:

In this next one we're asked to find the choice that is least relevant to making a certain decision. Thus, answering the other four questions will provide evidence that will either strengthen or weaken the rationale for the decision. You should read the stimulus while thinking about the kinds of things you might want to know before making such a decision. Here's the situation: The ad was placed to increase business, but most sales are made to people who have not seen the ad. Based on this evidence, the shop owner concludes that perhaps the ad should not be renewed. The evidence here concerns the majority of the shop's sales, but the conclusion involves canceling the ad—the implication being that the ad is not paying for itself. We wish to eliminate the four answer choices that contain information relevant to the decision; that is, that may offer clues as to whether the ad indeed pays for itself or not. Imagine that you are a business consultant, and consider whether you would ask the shop owner the question contained in each choice.

An 800 test taker is able to creatively envision the kinds of situations that might help him to evaluate answer choices.

(C) contains information irrelevant to the decision. Nothing in the original argument concerns the satisfaction of the shop's competitors. Even if competitors are not satisfied with the effects of their ads in trade publications, this particular ad in this particular publication may make money for this store. It may be interesting information for other reasons, but the answer to the question in (C) would not be very helpful in making the decision at hand, which makes (C) the correct answer.

(A)'s question would yield information particularly useful in making the decision. Although the ad doesn't bring in most business, it might bring in some, and that business might be worth more than the cost of the ad.

(B) may very well also produce information useful in making the decision. The existence of other, more productive uses for the ad money is certainly a pertinent consideration.

(D)'s question would reveal useful information. Even though most of the sales are not generated by the ad, the value of the sales that are might be relatively high. Knowing the number of big spenders the ad attracts would certainly aid in making the decision.

(E) fits well into the arsenal of pertinent questions. The future audience of the publication is crucial to assessing the wisdom of renewing the ad.
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Thank you for the detailed explanation