This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anxiety & Stress, Subject name: Psychiatry
Fear is due to: 
Select and explain. 
A. Abnormal experiences of childhood, B. Over conciousness, C. Excess perception of danger, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: D ref: Kaplan, 8th/e p. 557-558