All of the Following Are a Form of Polygamy EXCEPT

All of the following are a form of polygamy EXCEPT

A) a man who marries, then divorces, then marries again, then divorces again, then marries again, each time to a different woman.
B) a man who has four wives simultaneously.
C) a woman who has three husbands, all of whom are brothers.
D) a man who has three wives, all of whom are sisters.
E) a woman who has two unrelated husbands.