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.

With reference to the above passage, the following assumptions have been made:
I. Supply-side investments in companies can result in low-carbon behaviour in people.
II. People are not capable of adapting low-carbon behaviour without the involvement of Government and Companies.
Which of the above assumptions is/are valid?

The correct option is I only.

Step-by-step Explanation:

1. Analyzing the Passage:
The passage states that half of the required carbon emission reductions might be achieved through demand-side measures (individual/household behavioral changes). However, achieving this requires companies and governments to provide more incentives through supply-side investments to make low-carbon options cheaper and more widely available.

2. Evaluating Assumption I:
"Supply-side investments in companies can result in low-carbon behaviour in people."
The passage explicitly links supply-side investments by companies and governments (making low-carbon options cheaper and more available) to enabling and encouraging demand-side behavioral changes in individuals. Therefore, it is assumed that supply-side investments can indeed drive low-carbon behavior in people. Assumption I is valid.

3. Evaluating Assumption II:
"People are not capable of adapting low-carbon behaviour without the involvement of Government and Companies."
While the passage emphasizes that involvement/incentives from governments and companies are necessary to achieve "at best, half the reduction," stating that people are completely "not capable" of adapting low-carbon behavior on their own is an extreme generalization not strictly implied by the text. Therefore, Assumption II is invalid.

Hence, only Assumption I is valid.