C. it received support from western African empires.
Explanation:
In old arab text and Islamic history, the religion of Islam had started in modern day Arabia, which in the olden times was the lower part of the Ottoman Empire. The Ottoman Empire (along with the Mongols) ruled the upper part of Africa and Asia, soon traveling down to African area. Many countries and empires supported the widely spread religion, as stated in option C, so C would be your best take
