I believe the answer is A.
After the death of the amazing military and political leader Mansa Musa, his descendants argued over who would be the next ruler. This caused the empire to weaken greatly. Timbuktu was then raided and burned. The internal problems continued to worsen as the inhabitants of newly conquered territory started to rebel. The Songhai, in about 1365, led the Mali city of Gao to independence. by 1500, rebels and invaders had reduced the empire to the size that it had been when the Malinke people lived there.
