Well Arabic is a very good subject and an all the time scoring subject. I myself have this subject without it's background and I had 140 marks in my previous attempt. Therfore , I reckon Arabic can be opted without having background.
As well as Public Admin is concerned , it is an easier but low scoring subject. Especially , in 2012 it gave low scores.
However , if one has strong grip on some subject , one can go for any subject. Exceptions are always there. And those who are capable of creating exceptions , should take the challenges.