This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Defense Mechanism which explains “compulsions” in a patient of obsessive compulsive disorder? \nSelect and explain. \nA. Reaction formation, B. Regression, C. Undoing, D. Displacement', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Undoing explains compulsions in patients of obsessive compulsive disorder', 'role': 'assistant'}]