UPSC Prelims 2021— Question 79

The Common Carbon Metric is a methodology associated with measuring the energy use and carbon footprint of buildings/building operations. It was developed to create a comparable way of assessing emissions associated with building energy performance. It is not a mechanism for farm carbon trading or a general national fossil-fuel accounting tool. Hence the building-footprint option is correct. The final answer-key position for Set C identifies option A as the correct option. Option A — assessing the carbon footprint of building operations around the world — is correct because it is the alternative that matches the constitutional, historical, geographical, scientific or economic principle established above. Option B — enabling commercial farming entities around the world to enter carbon emission trading — 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 — enabling governments to assess the overall carbon footprint caused by their countries — 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 — assessing the overall carbon footprint caused by the use of fossil fuels by the world in a unit time — 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.