According to this Psychological school of thought to understand-19331

According to this Psychological school of thought, to understand human behavior and thought, one must understand the unconscious mind and the key events that happened early in life that influence the unconscious mind. What is this school of thought?

This multiple choice question (MCQ) is related to the book/course vu psy101 Introduction to Psychology. It can also be found in vu psy101 Final Term - Quiz No.8.