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': 'What is the major source for histamine released during inflammation? \nSelect and explain. \nA. Platelets, B. Mast cells, C. Basophils, D. Endothelial cells', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Mast cells are the richest source of histamine', 'role': 'assistant'}]