I am not completely sure but I think it's 'agrarian'.
Answer:
The ban against enslaving Muslims was observed very strictly in Hausaland in many ways. For example. if a non-believer would become a Islamic so called "believer", he would no longer would be someone's possession (slave). This is somewhat illogical because anyone could say that they are a Muslim just to become a free man or woman.
Explanation:
I majored in History
A country needs rules about citizens cause in reality you cant have random people, bad record or not, coming in your country and just being a citizen instantly without any proof of trust, little do they know they could be a terrorist with the rights of a citizen just cause theirs no way to justify who's one or not.
D I hope that is the answer