This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Pharmacology, Subject name: Pharmacology
[{'content': 'True about orphan drugs: \nSelect and explain. \nA. Drug used for orphans, B. They are rare drugs, C. They are emergency drugs, D. Drugs for rare diseases', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. (d) Drugs for rare diseases', 'role': 'assistant'}]