This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anxiety disorders stress disorders and grief, Subject name: Psychiatry
[{'content': 'Most common major symptom of obsessive-compulsive disorder is \nSelect and explain. \nA. Compulsive washing of hand, B. Compulsive thinking about same, C. Compulsive checking, D. Obsessive precision', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Compulsive washing of hands is the commonest type. Here obsession is of contamination with di, germs, body excretions and the like. Compulsion is washing hands or the whole body, repeated many times a day. It usually spreads on to washing clothes, washing of bathroom, door knobs, and personal aicles gradually (Ref: a sho textbook of psychiatry, Niraj Ahuja,7th edition, pg no 95)', 'role': 'assistant'}]