Well any letter that well written would get my attention.
I'd be impressed by the arguments put forth in sentences 2 and 4.
Four is the tricky one because you really want to choose 3. The problem with three is that it introduces the argument. It does not provide the details needed to clinch the argument. That requires 4. Look at the reasons.
1. jobs.
2. after school activities.
3. exhaustion by the time of getting to the homework
4. a longer lunch = homework done with more accuracy. Lots of reasons.
Two is very straightforward.
1. no complaints about the staff (always a good move in an argument. Note it, don't use it.)
2. long lines.
3. vending machines become the lunch servers.
4. the nurse says it's unhealthy. Now there's an argument worth noting.
One is an introduction to the letter and five is a conclusion plus a note about a petition. It's a very well thought out letter.