Answer:
The answer is: The trash associated with the vending machine.
Step-by-step explanation:
When you read the excerpt above, you see what the problem is especially in these lines: "The teachers and custodians are not as enthusiastic. They complain about the wrappers, containers, and peelings that litter the floors and hallways."
The wrappers, containers and peelings i.e trash were clearly a source of concern to the teachers and custodians. To the point that they wanted a trial period where students have to keep the school clean or risk losing their vending machine.
Putting the above in mind, you can therefore see that the answer is: the thrash associated with the vending machine.