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': 'Primordial prevention in coronary heart disease: \nSelect and explain. \nA. Salt restriction, B. BP monitoring, C. Exercise in high risk area, D. Statins', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]