The answer is (D).
Blacks lived in the Bantustan territory, so it’s not B. Also, apartheid is the segregation and discrimination of blacks. So, choices A and C don’t make sense either.
"<span>a. the size of their military" would be the best option from the list, since they greatly outnumbered the colonists and their militias. They were also far-better trained as soldiers. </span>