A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of studying and noise. It is a general statement that does not need other sentences for context. It does not start with a conjunction or use pronouns. It also does not use the definite article 'the' for a defined subject. Why other lines are not chosen? The other paragraphs are not chosen because: 1) Paragraph 2 starts with 'Others,' which is a pronoun that refers back to a previous idea. 2) Paragraph 3 starts with 'The point is,' which is a transitional phrase. 3) Paragraph 4 starts with 'However,' which is a conjunction and needs prior context.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the discussion about noise and studying. It gives a clear rule that students should follow. It summarizes the main ideas and provides a conclusion about distractions.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects with Paragraph 1 because it shows a contrast. The word 'Others' indicates a different group of students who have a different opinion about noise. This is a clear use of the 'Contrast' rule.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects with Paragraph 2 because it explains the main idea further. It gives a conclusion about understanding what noise level works best for studying. This follows the 'Logical Order' rule.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects with Paragraph 3 because it gives a general rule about noise while studying. It adds more information about distractions. This follows the 'Broader to Specific Strategy' rule.