Dell Laptop Help - wireless internet card/ wifi card?

I am buying a inspiron 15, and am wondering which thing for the internet would be best:
Dell Wireless 1515 Half Mini Card (802.11n)
Dell Wireless 1397 Mini Card (802.11 b/g)
Intel WiFi Link 5100 (802.11 a/b/g/n 1X2) 1/2 MiniCard

and also what is the difference between them??

any help would be appreciated, thanks