The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Vasopressin antagonist acts on which pa of the nephron?   (A) Proximal convoluted tubule   (B) Distal convoluted tubule   (C) Coical collecting tubule   (D) Medullary collecting duct
['(D) Medullary collecting duct <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Proximal convoluted tubule \n (B) Distal convoluted tubule \n (C) Coical collecting tubule \n (D) Medullary collecting duct <> possible answers', '  Vasopressin antagonist acts on which pa of the nephron? <> context@']