Sustainability is about maintaining the ecosystem diverse and productive, even attending the needs of production for humanity as well.
In order to do so, it's important to be careful about the disposal of any types of trash. So, avoiding to dispose of trash unnecessarily is really important, therefore A is correct. It is also important to avoid creating unnecessary trash, what happens when we chose to consume only water from plastic bottles, for example, instead of using reusable bottles. This means that B is also correct. Talking about not creating unnecessary trash, C is also correct, because it talks about avoiding single-use products. Also, avoiding the creation of unnecessary trash is related to E, because it's about avoiding excess packaging and/or avoid buying unnecessary items, reusing the same ones instead. Therefore, alternative D is incorrect, because while it talks about recycling it also incites the usage of plastic bags to dispose trash, which could be replaced by paper bags, for example.