Answer:
Hello, If you are trying to persuade your principal on improving school lunches the best is to use formal language.
Step-by-step explanation:
For example: You could write something like: I am (your name) and the reason of this letter is to inform you that many students are a bit tired of eating the same every day. For that reason, I would like to ask you If it is possible to change the menu.
Looking for a favourable response,
Thanks in advance.