Answer:
Hiya!
Hope I can be of help.
First, I encourage you to read each choice very carefully and ask yourself what each one is trying to say. Simplify it and then distill it to its main point.
I'll go through each.
1) Cows certainly eat a bunch of grass, however the sentence we're working with doesn't mention cows or their gluttonous eating habits.
2) The assertion that most people like plant burgers may very well be true (although I doubt it lol), but once again that has nothing to do with our sentence.
3) Ahhh, here we have the answer! The fact that school cafeterias (notorious for their terrible food) are starting to have "vegetarian day" shows that excluding meat from ones diet has become much easier.
4) You can certainly eat meat and be planet conscious, but again our sentence doesn't address that at all!
Hopefully that helps. English can be fun ;)
Happy trails, learner!