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: Pathology
[{'content': 'The Triat in which the parents are clinically normal and only siblings are affected but males and females are affected in equal propoions is: \nSelect and explain. \nA. AD, B. AR, C. XLD, D. XLR', 'role': 'user'}, {'content': 'Answer: B \nExplanation: AR', 'role': 'assistant'}]