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: Pathology
[{'content': 'Bone marrow aspiration is not indicated in : \nSelect and explain. \nA. Thalassemia major, B. Megaloblastic anaemia, C. Idiopathic thrombocytopenic purpura, D. Pure red cell aplasia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]