Books updating the classification systems used by many libraries are not free—in fact they are very expensive. The only way to sell copies of them is to make the potential buyers believe they need to adopt the most recent system. Thus, these frequent changes by the publishers to make libraries buy their products.
What this question is testing
Your task
Describe the reasoning error the argument actually commits.
Common trap
Answers that name a real logical flaw the argument doesn't actually make.
Winning move
Articulate the gap in the reasoning yourself, then match it to the choice that describes that gap.
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