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': 'Russell’s body is found in: \nSelect and explain. \nA. Metastatic calcification, B. Plasma cells, C. RBC, D. Mast cells', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Russell bodies are large homogenous eosinophilic inclusions formed by hugely distended endoplasmic reticulum\xa0of plasma cell.\nTheir formation is triggered by synthesis of excessive amount of normal secretory proteins in plasma cells.', 'role': 'assistant'}]