This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: RDA, Nutritional Requirements, Subject name: Social & Preventive Medicine
[{'content': "'Twin foified salt' contains: \nSelect and explain. \nA. Iodine + Fluorine, B. Iodine + Calcium, C. Iodine + Iron, D. Iodine + Chlorine", 'role': 'user'}, {'content': "Answer: C \nExplanation: National Institute of Nutrition (Hyderabad) developed 'Twin Foified Salt' also known as 'Double Foified Salt' (DFS) to prevent iron & iodine deficiencies. DFS - contains Iron and Iodine contains salt, Potassium Iodinate, Ferrous sulphate and sodium hexa metaphosphate. provides 40 mcg Iodine and 1 mg Iron per gram of salt.", 'role': 'assistant'}]