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': 'In primary pulmonary hypertension basic abnormality in gene lies in - \nSelect and explain. \nA. Bone morphogenetic protein receptor II, B. Endothelin, C. Homeobox gene, D. PAX-11', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]