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: Anatomy
[{'content': 'BMP -4 is inhibited by A/E \nSelect and explain. \nA. Noggin, B. Follistatin, C. Retinoic Acid, D. Chordin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Retinoic Acid', 'role': 'assistant'}]