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: Pharmacology
[{'content': 'Orange coloured urine is due to: \nSelect and explain. \nA. Rifampicin, B. INH, C. Pyrazinamide, D. Ethambutol', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The urine and the secretions of the patients receiving Rifampicin becomes orange-red and it is harmless. Such a side effect is not encountered with the other three anti-tubercular drugs mentioned as choices. Ref: K D Tripathi Textbook of Pharmacology, 5th Edition, Pages 698-701', 'role': 'assistant'}]