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': "'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 sat' DFS contains salt, potassium iodide, ferrous sulphate and Sodium hexa meta phosphate DFS provides 40 mcg Iodine and 1 mg Iron Per gram of salt Ref: Park 22nd edition Pgno : 597", 'role': 'assistant'}]