This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition and health, Subject name: Social & Preventive Medicine
[{'content': 'Codex alimentarius is related to - \nSelect and explain. \nA. Water purity, B. Milk purity, C. Air polution, D. Food stardardization', 'role': 'user'}, {'content': "Answer: D \nExplanation: Food standards are done by CODE ALIMENTARIUS, PFA STANDARDS, THE AGMARK STANDARDS, BUREAU OF INDIA STANDARDS. REF. PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICAL 21ST EDITION. PAGE NO - 610)", 'role': 'assistant'}]