UPSC Prelims 2021— Question 94

Demand for a good rises when the price of a substitute rises because consumers shift toward the good. A fall in the good's own price changes quantity demanded rather than demand, so statement 4 is not a demand-shift condition. A higher complement price reduces demand, and an increase in income reduces demand for an inferior good. Thus only statement 1 is correct. The final answer-key position for Set C identifies option A as the correct option. Option A — 1 and 4 only — is correct because it is the alternative that matches the constitutional, historical, geographical, scientific or economic principle established above. Option B — 2, 3 and 4 — is not correct because it does not satisfy the specific condition tested in the question; it represents an alternative that is contradicted, incomplete, or less precise than the accepted answer. Option C — 1, 3 and 4 — is not correct because it does not satisfy the specific condition tested in the question; it represents an alternative that is contradicted, incomplete, or less precise than the accepted answer. Option D — 1, 2 and 3 — is not correct because it does not satisfy the specific condition tested in the question; it represents an alternative that is contradicted, incomplete, or less precise than the accepted answer. For PYQ interpretation, the distinction between the correct alternative and merely related facts is important. UPSC often places plausible distractors beside the precise statement that matches the underlying rule, chronology, definition or empirical relationship. The answer should therefore be read against the exact wording of the question rather than against a broadly related fact.