Which one of the following statements best reflects the most logical, rational and practical suggestion implied by the passage?
Answer & explanation
Answer: (b) This can be used as one of the methods of carbon sequestration.
Carbon dioxide pumped into basalt ends up locked in stone (limestone). The practical suggestion is to use this as a way of storing carbon dioxide permanently, that is, carbon sequestration.
- ✗ (a) The passage says nothing about cost or about commercial limestone for building; its point is where the carbon dioxide goes.
- ✓ (b) ‘Basically carbon dioxide is converted into stone’: locking carbon dioxide away in solid rock underground is carbon sequestration.
- ✗ (c) The rock’s calcium and magnesium are used up in forming limestone; the method does not make basalt a source of these minerals.
- ✗ (d) The acidic mixture is only a step in the process; making acid is not what the finding is useful for.
Remember · Ask what problem the finding solves. The key word here is carbon dioxide, so the answer concerns climate, not construction.
Question and answer: UPSC's official GS Paper II (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·