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': 'In calculating RDA for a particular nutrient, 2 SD are not added for \nSelect and explain. \nA. Iron, B. Calcium, C. Energy, D. Vitamin A', 'role': 'user'}, {'content': "Answer: C \nExplanation: Recommended Dietary Allowance (RDA): Is a level of intake corresponding to Mean + 2 Standard Deviation, which\xa0covers requirement of 97.5 % of population\n\nRDA is safe level of intake which is likely to be inadequate in not more than 2.5 % population\nRDA 'safe level approach' is NOT USED FOR ENERGY since excess energy intake is undesirable; For energy only\xa0mean or average requirement is defined as RDA.", 'role': 'assistant'}]