There is no such thing as the "best" antivirus.
Personally nowadays I don't feel any need to pay for an antivirus program - If you use the free edition of Avast and then run a scan with Malwarebytes (Free) every once in a while you'll be fine.
Your antivirus program only goes so far, common sense is much more important - Don't download or run things from sources that you don't trust.
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