The choices can be found elsewhere and as follows:
A). Zimbabwe was a highly productive agricultural society.
B).Fish from Zimbabwe were a staple food of East African people.
C).Zimbabwe's military was stronger than others in the region.
D).Zimbabwe controlled the region's ivory and gold trade.
I believe the correct answer is the second option. A eason for great zimbabwe's rise to power would be that fish from Zimbabwe were a staple food of East African people.