If I had to choose from that three,it would be Bit Defender but I would recommend kaspersky
Kaspersky. Your favorite AV <3.
Use AVAST its free and light.
AVG and BitDefender suck in my opinion, I'd honestly go with Avira or Malware Bytes, they're the best evar!
Well to start, your computer is perfect for any antivirus.
I previously used Norton as my #1 antivirus and firewall.
I then switched to BitDefender and I wasn't to happy at all.
I suggest using either AVG or Eset NOD 32.
They are both great.