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': 'Dosage of topical tobramycin eye drops : \nSelect and explain. \nA. 1 mg/ml, B. 2 mg/ml, C. 3 mg/ml, D. 4 mg/ml', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]