Select the most appropriate option to fill in blank number 3.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. must.
The sentence emphasizes the necessity for nations to take action against climate change.
Must expresses a strong obligation or requirement.
The other options are incorrect because:
- Would suggests a hypothetical situation, which weakens the urgency.
- Could implies a possibility, but here the sentence demands a stronger commitment.
- Might expresses uncertainty.