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': 'Morula is a stage of cell \nSelect and explain. \nA. 8, B. 16, C. 32, D. 64', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]