Which of the following describes the middle passage of the triangular trade route?
a: the transport of slaves from africa to the americas, during which nearly 20 percent of slaves died
b: the transport of manufactured goods from europe to africa, where they were traded for slaves
c: the transport of slaves from america to europe, where they were traded for tobacco and sugar
d: the transport of goods from africa to europe, during which nearly 20 percent of sailors contracted smallpox