CSAT Solved Papers/ 2025/Q41
2025 CSAT — Q41
Passage
Over the next 30 years, many countries are promising to move to net-zero carbon, implying that household emissions will have to be cut to close to nothing. A leading climate scientist reckons that, at best, half the reduction might be achieved through demand-side measures, such as behavioural changes by individuals and households. And even that would require companies and governments to provide more incentives to change through supply-side investments to make low-carbon options cheaper and more widely available.
Which one of the following statements best reflects the central idea conveyed by the passage?
Thinking pathway
Locate. This asks for the central idea, so find the claim the passage exists to make. The passage concedes that “at best, half the reduction” comes from demand-side behaviour, then pivots on its key word — incentives: “even that would require companies and governments to provide more incentives… to make low-carbon options cheaper.” The through-line is that behaviour follows incentives. That is the anchor.
Test (thesis-vs-detail + scope-fit). The key must state that low-carbon behaviour is driven by incentivising people, no more. (b) — “Low-carbon behaviour in people can be brought about by incentivising them” — matches the through-line precisely.
Eliminate by anatomy. (a) over-states the case and gets the direction backwards — “possible only by reduction in household emissions” contradicts the passage’s “at best, half.” (c) is half right, half wrong — the passage says supply-side investment makes low-carbon options cheaper, not “goods and services” generally; it quietly broadens the claim. (d) is a claim the passage never actually makes — “subsidies to manufacturing industries” is a specific instrument the passage never names; it mentions incentives broadly, not sector subsidies. Key: (b).
Evidence in the text
“even that would require companies and governments to provide more incentives to change through supply-side investments to make low-carbon options cheaper and more widely available.” The passage’s point is that behavioural (demand-side) change happens only when companies and governments incentivise it — i.e. low-carbon behaviour is brought about by incentivising people (b).
Worked rationale
The passage argues that demand-side behavioural change can deliver at most half the needed cut, and that “even that would require companies and governments to provide more incentives… to make low-carbon options cheaper and more widely available.” The central idea is that low-carbon behaviour is brought about by incentivising people (through companies and governments).
(b) states this. Answer: (b).
Why the other options miss
- A over-states the case: “possible only by the reduction in household emissions” contradicts the passage’s “at best, half the reduction” from demand-side measures.
- C half right, half wrong: the passage says supply-side investment makes low-carbon options cheaper; (c) broadens this to “cheaper goods and services” in general, a claim the text does not make.
- D a claim the passage never actually makes: “subsidies to manufacturing industries” is a specific policy instrument the passage never specifies; it speaks of incentives generally.
Specialist insight
The discriminator is scope. (a) over-claims (only households), (c) over-broadens (all goods and services), (d) over-specifies (industry subsidies). (b) keeps exactly the passage’s scope: behaviour ← incentives. On a central-idea question, the option that neither narrows, broadens, nor sharpens the author’s actual claim is the key.
(c) broadens "low-carbon options cheaper" into "goods and services cheaper"; the central idea is that behaviour follows incentives — (b).