Which of the Following Statements Is True About the Beginnings

Which of the following statements is true about the beginnings of European slavery?

A) The Portuguese who traded with African kingdoms bartered for African slaves and carried them back to Portugal as living novelties.
B) Slavery was a prominent form of labor and was based on one's race throughout the fifteenth century.
C) The first modern economy dependent primarily on race-based slavery was established by the English in the late 1300s.
D) The preoccupation with race-based slavery declined in the late sixteenth century.
E) Most of the slaves used by the Portuguese were free laborers who came from different professions.