I'm not 100% sure on these but here are my best guesses:
I would say B.), D.), and E.).
A.) Doesn't seem correct because I've never heard of people becoming slaves because of criminal acts.
B.) Does seem correct because look at the indentured servants, they weren't technically called slaves but they were forced to work for years for whomever paid for them to travel to the colonies.
C.) Doesn't seem correct because I've never heard of people becoming slaves because they didn't know the right people.
D.) It seems odd, but I suppose it could have happened. Slaves for work and such.
E.) Prisoners of war can and have been enslaved.
Hope this helps! (:
