What Was One Reason That African Slavery Replaced Indentured Servitude

What was one reason that African slavery replaced indentured servitude as the primary labor source in the late seventeenth century in the Chesapeake colonies?

A) The death rate in the American colonies had risen considerably, especially due to harsh winters.
B) Bacon's Rebellion showed colonial leaders that slaves had been given too much freedom.
C) The Royal Africa Company acquired a monopoly on the English slave trade.
D) Pennsylvania had been closed off due to a lack of available land there.
E) As the economy improved in England, people were less likely to come to the colonies.