A colleague, Xiao Li, recommends a course and says: “This course is definitely worth the price.” When Sister Wang asks why, Xiao Li replies: “Look, it is priced at 980, and the course provider would never set a price that the course isn't worth.” Sister Wang asks again: “But how do we know that price is reasonable?” Xiao Li answers: “Because the course is worth that price — otherwise they wouldn't have set it.” Which of the following evaluations is most accurate?

Answer: A

• AXiao Li's final reason merely asserts that the pricing is reasonable, which is the same thing as the claim he set out to prove, that the course is worth the price; the argument goes in a circle and proves nothing.✓ Correct. Restated in the plainest words, “worth the price” and “the price is reasonable” are the same thing; the reason holds only if you already accept the conclusion, which is a classic circular argument.
• BXiao Li's reason rests on the authority of the course provider as the seller, making it an appeal to illegitimate authority, but it at least offers some new information beyond the price itself.✗ Wrong. This misreads the problem as being about “who said it.” The flaw here is not authority but that the reason is just the conclusion rephrased, providing no new support at all.
• CXiao Li's reason has nothing to do with whether the course is valuable, making it an irrelevant reason, so the argument is not circular but merely invalid.✗ Wrong. The reason is not irrelevant — it precisely repeats the conclusion. Applying the label of “irrelevant reason” here overlooks the fact that the reason and the conclusion are one and the same thing.
• DThat the price is reasonable is a commonly accepted fact requiring no further justification, so Xiao Li's statement, though simplistic, still stands.✗ Wrong. This mistakenly assumes that a reason accepted as common sense cannot be circular; here the reasonableness of the price is exactly the conclusion to be proven, not independent common knowledge.