camp in the woods use biodegradable materials visit a landfill use disposable plates
I gave my students this multiple choice question: Which of the following is a way that everyone can help with conservation efforts?

Only one answer is correct among these 4 choices:
- camp in the woods
- use biodegradable materials
- visit a landfill
- use disposable plates

Could you tell me which one is correct?

use biodegradable materials