According to McIntyre, Which Statement Is False

According to McIntyre, which statement is false?

A) Slavery is a form of the caste system (and slaves are the "outcastes") .
B) Members of any social group might become slaves in some circumstances.
C) Some people have sold themselves into slavery.
D) In most societies where it existed, slavery begins as an achieved status, and then may come to be ascribed.
E) Under some conditions, slaves can be manumitted.