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: Social & Preventive Medicine
[{'content': 'Visual activity cut off for the referral to PHC is, \nSelect and explain. \nA. <6/18, B. <6/6, C. <6/9, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]