What factors led to the fall of the empire of ghana?

Around 1050 AD, the Empire of Ghana was pressured by northern Muslims to convert to Islam. The kings of Ghana refused and soon suffered constant attacks from North Africa. At the same time, a group of people named Susu freed themselves from Ghana. Many years of war and the loss of its natural resources led to the fall of Ghana in the thirteenth century.

could you give me the options ?

uncle sam would be tossing and turning in his grave : *)