How Can the English Translated Word Slave Be Related to the Islamic

How can the English translated word slave be related to the Islamic trade?

A) Muslim trade predominantly involved slaves from "slav" lands in central and eastern Europe. 
B) Slaves taken from central Europe were very often Slavic.
C) Islam did not allow the sale and purchase of slaves.
D) Muslim trade involved slaves from central Asia.
E) Peoples in central Europe who refused to convert to Islam were sold into slavery.