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: Microbiology
[{'content': 'All are seen in the cyst of E. histolytica except - \nSelect and explain. \nA. Glycogen mass, B. Chromatid bars, C. Eccentric nucleus, D. Refractile nucleus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]