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: Medicine
[{'content': 'Spontaneous mouth petechiae and gingival bleeding occur typically at platelet levels \nSelect and explain. \nA. Between 300,000 - 500,000/mm3, B. Between 20,000-30,000/mm3, C. Between 150,000-170,000/mm3, D. Between 70,000-185,000/mm3', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]