This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
[{'content': 'A 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: A cluster headache is a rare, primary headache (0.1%)The pain is deep, retro-orbital, excruciating, non-fluctuating, and explosive in quality.Unilateral pain for 8 to 10 weeks a year, followed by a pain-free intervalMen are affected three times more often than women.Patients with a cluster headache become aggressive during attacks.Parasympathetic autonomic activation: Ipsilateral symptoms of cranial conjunctival injection or lacrimation, rhinorrhea or nasal congestion, or cranial sympathetic dysfunction such as ptosis.The sympathetic deficit is due to injury to ascending sympathetic fibers surrounding a dilated carotid aery as it passes into the cranial cavity.Ref: Harrison; 19th edition', 'role': 'assistant'}]