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: Medicine
[{'content': 'A 70 years old male develops pneumonia and septicaemia. Patient goes into renal failure and has a B.P of 70/50 mm of Hg. Drug that should be used to maintain B.P is \nSelect and explain. \nA. Adrenaline, B. Ephedrine, C. Phenylephrine, D. Nor epinephrine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]