Do you have MS Outlook (not express) installed on your system ?
If not the Outlook/Exchange provider isn't required, the Internet Mail provider provides protection for normal pop3 email like OE, Thunderbird, etc.
I suggest you also consider what the other providers do as you may not need them all running, If you don't use Instant Messaging (IM) or P2P or you don't know what they are you may not require it.
A browse of the avast help file, Resident protection give a description of all the providers and their settings so you should be able to confirm which you need enabled.