As far as I am concerned Gao was not one of the Songhay Empire's major ones but I bet two answers should be acceptable in this question. I also think that you can include the third option from the scale represented above because <span>Algiers were quite far away on north so they couldn't be the part of the Songhay. </span>
The answer would be letter B.
He taught them discipline and military strategies used by other armies in order to help them become more professional.
Answer:
B pretty sure
Explanation: B because they became a sharecropper because of debt in the first place and when they were there their owners wouldn't give them much of a salary at all and they legally couldn't sell their own crops.