All of the following are true statement about the powerful african slaves known as the mamluks except
a. they had been captured as children.
b. they were forced to convert to islam.
c. they controlled the greater portion of west africa.
d. they were trained to serve the sultan as cavalier soldiers.

The answer is C, they were forced to convert to Islam. 
The Mamluks were a class of warrior slave, mostly of Turkic or Caucasian ethnicity, who served between the 9th and 19th century in the Islamic world. Despite their origins as slaves, the Mamluks often had higher social standing than free-born people.