The Major Contribution of Emil Kraepelin Was ________

The major contribution of Emil Kraepelin was ________.

A) the development of a classification system that forms the cornerstone of current diagnostic systems
B) the discovery that early childhood environment plays a crucial role in the development of a healthy personality
C) the discovery of the bacterium causing syphilis
D) the development of "moral therapy," in which humane treatment and a relaxed environment were used to help restore mental health