Query about mail settings.If Avast

If Avast finds an infected e-mail, there are three options in the settings box. They are “let it be delivered to your inbox”…“discard unconditionally”…and “move to folder”. Can anyone tell me which is the most appropriate setting? At the moment I’m set to deliver to inbox, however I suspect move to folder might be the one to use.
If so,as a novice could you give me full, simple instructions please.
Thanks everyone.

The safe thing to do is discard it. If you want to save it for further investigation move it to folder. If you want to roll the dice let it be delivered.
-max