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: Physiology
[{'content': 'Following  cells  are  responsible  for acid secretion in kidney: \nSelect and explain. \nA. I cells, B. P cells, C. Mesangial cell, D. Pericytes', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Two types of cells in CD & DCT:\nP (Principal) cell is responsible for:\n\nNa+ reabsorption\nK+ secretion\nH2O Absorption\n\nI (Intercalated) cell: two types\n\nAlpha: acid secretion\nBeta: HCO-2 secretion', 'role': 'assistant'}]