Choose the correct answer by crossing A, B, C, D, or E!

This text is for questions 32 to 34.

    When the school bell rings, all students rush to their classrooms. Then the school gardener with a couple of large garbage bags picks up the trash. I'm sad to see this situation. I think there are some reasons why students l itter everywhere and the school needs more trash bins.

    The headmaster and teachers must have insisted that litter can be reduced if students become more responsible. Most of the students are pretty good about it, but not all of them. I have asked some gardeners that they need 15 to 20 minutes to pick up most of the litter. The excess of litter on school can only be attributed to laziness and a lack of concern. Students who are in a rush sometimes leave their trash behind. Moreover, the trash bins are located in the wrong places.

    Students can easily dispose of their spare trash on the way to their classes. Adding to the problem, many students do not dispose of their recyclable products properly. If someone does not pick the litter up, something will. Animals, such as birds, often scavenge the remains of food, posing a significant health concern for the animals. If an animal does not find it, the litter starts to decompose. It is harmful to the environment. Most plastics are not biodegradable, and the chemicals in cups, wrappers, and trays are harmful for the environment.

    For those reasons, I think students must be aware of this matter. That's why the school needs the installation trash bins which take only a 20-second walk.

What is the issue of the text?