A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of financial management. It sets the stage for the rest of the text. It does not refer to any previous information. Why other lines are not choosen? The other paragraphs are not chosen because they do not meet the criteria for being independent. For example, Paragraph 2 starts with 'They', which is a pronoun and needs context. Paragraph 3 starts with 'Once', which is a conjunction. Paragraph 4 starts with 'This', which also needs context.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the main ideas. It shows the results of their efforts in financial management.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): This pair connects because Paragraph 2 explains what they did after realising they needed a better approach. It follows a logical order of thought.
• Pair 2 (Paragraph 2 → Paragraph 3): This pair connects because Paragraph 3 shows the next step after finding the right tool. It follows a logical order of actions.
• Pair 3 (Paragraph 3 → Paragraph 4): This pair connects because Paragraph 4 explains the benefits of the system they used. It shows how the tool helps them.