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': 'The Iodine content in iodized salt at production point should be: \nSelect and explain. \nA. 10 ppm, B. 20 ppm, C. 30 ppm, D. 40 ppm', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 30 ppm', 'role': 'assistant'}]