The practice of drilling circular holes in the skulls of people displaying abnormal behaviors in order to free evil spirits was known as

A) trephination.
B) exorcism.
C) atonement.
D) blood letting.

Trephination, also known as trepanation, was a common practice in many ancient cultures. It involved drilling or cutting circular holes in the skull to release evil spirits or relieve pressure from head injuries or other ailments. It was believed that the evil spirits residing in the brain caused abnormal behaviors and by removing them, the person could be cured.