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: Medicine
[{'content': 'Cluster headache is characterized by all, except: \nSelect and explain. \nA. Affects predominantly females, B. Unilateral headache, C. Onset typically in 20-50 years of life, D. Associated with conjunctival congestion', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (Affects predominantly females) : Cluster headache affects predominantly males. Men are affected 3 times more often than women.', 'role': 'assistant'}]