Answer:
D. They died too much from diseases and weren't used to intensive agriculture.
Step-by-step explanation:
A is not the answer because if they were too small, then white plantation owners would not be using the children of slaves to work on the fields.
B is not the answer because Native Americans did not listen to country music but their native music.
C is not the answer because Native Americans did not work on agriculture much and were more focused on hunting as a means of survival.
So, this leaves us with A as the only solution left that has yet to be crossed out.