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': 'In cotrimoxazole, sulphamethoxazole and trimethoprim are in ratio of: \nSelect and explain. \nA. 2:01, B. 1:01, C. 5:01, D. 4:05', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 5:01', 'role': 'assistant'}]