UPSC Prelims 2014— Question 44

Correct answer: Option D. Steel production can release several atmospheric pollutants, including sulphur oxides, nitrogen oxides, carbon monoxide and carbon dioxide, depending on fuel, ore processing and industrial processes. The question therefore treats all four as important pollutants associated with the industry. Option A: Incorrect. This option does not match the verified answer because its proposition, location, institution, sequence, or combination conflicts with the relevant fact tested in the question. The option reads: “1, 3 and 4 only” Option B: Incorrect. This option does not match the verified answer because its proposition, location, institution, sequence, or combination conflicts with the relevant fact tested in the question. The option reads: “2 and 3 only” Option C: Incorrect. This option does not match the verified answer because its proposition, location, institution, sequence, or combination conflicts with the relevant fact tested in the question. The option reads: “1 and 4 only” Option D: Correct. This option is consistent with the governing fact or the valid combination identified in the question. The option reads: “1,2, 3 and 4” The key Prelims lesson is to test each proposition independently before selecting the combination. Where the question uses words such as 'only', 'all', 'none', 'always' or a precise institutional/geographical association, a single inaccurate component is sufficient to eliminate the option. The answer recorded here follows the official answer key for the question-paper series represented by the uploaded source and has been cross-checked against an independent published key. The explanation is intended for conceptual revision rather than as a reproduction of any third-party solution.