WHICH PROFESSIONAL BODY IS BEST?

Hello house, pls i have the opportunity of taking professional examination on ADMINISTRATION (to be chattered) and so far their are various administrators chattered bodies. and it is kind of difficult to say which is more recognized in Nigeria.
Can some one in the house help out on this. i have heard of Institute of Registered Administrative Managers of Nigeria, Chattered Institute of Administration and so on. but i need info on the most recognized of them all. It is urgent.
Thanks