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': 'Which of the following is the most serious and life-threatening blood dyscrasias caused with a drug: \nSelect and explain. \nA. Aplastic anemia, B. Megaloblastic anemia, C. Thrombocytopenia, D. Hemolytic anemia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]