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': 'Part of the kidney unit involved in Arsenic Poisoning - \nSelect and explain. \nA. Collecting duct, B. Loop of henle, C. PCT, D. DCT', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]