Which of the Following Statements Is True of the West

Which of the following statements is true of the West African slave trade?

A) European merchants secured all their slaves by seizing them in raids deep within the interior of Africa.
B) European merchants waited on board their ships or in fortified port cities to purchase slaves from African merchants and elites.
C) Europeans possessed immunities to the diseases of the region,giving them an advantage in controlling the trade.
D) African rulers universally opposed the slave trade on humanitarian grounds and worked together to suppress it.