Why Were the Brazilian and Caribbean Plantations Such Deadly Places

Why were the Brazilian and Caribbean plantations such deadly places for African slaves in the colonial period?

A) Europeans generally worked African slaves to death because it cost less to replace them than to sustain them.
B) Africans were particularly susceptible to European diseases and as a result died in large numbers.
C) Like Europeans, African slaves were frequently victims of Native American raids on European settlements.
D) African slaves staged frequent revolts, which the Europeans regularly suppressed with massive executions.