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: Psychiatry
[{'content': 'Which of the following excludes painful stimuli from awareness - \nSelect and explain. \nA. Repression, B. Reaction formation, C. Projection, D. Rationalization', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Traumatic events (or painful stimuli) are repressed (forced down) in to unconsciousness, i.e. repression acts unconsciously to exclude anxiety provoking ideas or feeling from conscious awareness.', 'role': 'assistant'}]