UPSC Prelims 2015— Question 70

Correct answer: Option D. Ocean tides are produced mainly by the gravitational attraction of the Moon and the Sun, together with the Earth-Moon system’s orbital dynamics and associated centrifugal effect. The Moon is the dominant contributor because it is much closer to Earth. The simplified statement in the question treats the relevant gravitational and centrifugal components together, making all three listed factors part of the explanation. Option-wise analysis: Option A: “1 only” is incorrect. It does not match the specific fact, definition, institutional role, geographical association, or constitutional/economic principle required here. The key distinction is the one identified in the core explanation, so this option can be eliminated. Option B: “2 and 3 only” is incorrect. It does not match the specific fact, definition, institutional role, geographical association, or constitutional/economic principle required here. The key distinction is the one identified in the core explanation, so this option can be eliminated. Option C: “1 and 3 only” is incorrect. It does not match the specific fact, definition, institutional role, geographical association, or constitutional/economic principle required here. The key distinction is the one identified in the core explanation, so this option can be eliminated. Option D: “1, 2 and 3” is correct. It directly matches the factual or conceptual requirement tested by the question and is supported by the principle explained above. Prelims takeaway: Focus on the precise institutional role, constitutional provision, geographical association, or technical definition being tested. UPSC questions often place a broadly familiar fact beside a narrowly incorrect qualifier; identifying that qualifier is essential for elimination.