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': 'How is the protein Energy Ratio (PER) in diet expressed as – \nSelect and explain. \nA. Energy in diet/Protein in diet x 100, B. Protein energy in diet/Total energy in diet  x 100, C. Total protein in diet/Total energy in diet x 100, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Protein energy ratio (Protein energy percentage) \n\nIt is a quantitative measure for assessment of protein.\nIt measures the percentage of energy that is provided by the protein in the food.\n\nPE percent = Energy from protein /\xa0Total energy in diet x 100\n\nIf the PE ratio is less than 4%, the subject will be unable to eat enough to satisfy protein requirements.\nIt is recommended that protein should account for approximately 15 to 20% of the total daily energy intake.', 'role': 'assistant'}]