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: Medicine
[{'content': 'Which of the following is least characteristic of anorexia nervosa –  a) Lowered vital signs when the weight is low  b) Decreased physical activity  c) history of obestity  d) Denial of illness \nSelect and explain. \nA. ab, B. bc, C. cd, D. bd', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]