What Triggered the Economic Collapse of Ghana in the Late

What triggered the economic collapse of Ghana in the late eleventh century?

A) The arrival of Muslim traders redirected West African commerce across the Sahara.
B) A series of droughts undermined the agricultural foundation of Ghana's economy.
C) A wave of epidemic diseases devastated the population.
D) The intensification of the slave trade diverted Ghana's economy from productive industries to a single-minded and destructive focus on enslaving neighboring peoples.