Qatar does not offer a business class product on many middle eastern sectors including Cairo. Instead it labels its business class as F which is what you have encountered. Chances are that your underlying ticket is at the P "lite" fare. As such you will not have access to AS first class lounge. Your status which might have overridden this if it were from QR, appears to be from AA. As such your guaranteed options would be the platinum lounge or the gold and platinum lounge by gate C14. You can of course try AS.