Putnam's wife was revengeful because

she thought that witchcraft and the supernatural were to blame for the deaths of her unborn children
her husband had an affair
her husband had been wronged by the church
her husband was cheated out of land

she thought that witchcraft and the supernatural were to blame for the deaths of her unborn children.

In The Crucible, Anne Putnam, the wife of Thomas Putnam, had lost seven children out of the eight she had. As she is a supersticious person, she believes these children were killed by witchcraft. Thomas Putnam, on the other hand, also believes that witches should be persecuted. However, his motives are financial.

a, b, and c are all correct.

she was trying to use   reliable narrator.