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: Dental
[{'content': 'While recording the rest position of the mandible, the patient’s head position should be \nSelect and explain. \nA. Head should be upright and unsupported, B. Head should be supported by the head rest, C. Patient should be lying in repose position, D. The neck should be extended', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In this position, action of the muscles that regulate mandibular\xa0position is equalized and mandible is free of any undue pull of any\xa0muscle.', 'role': 'assistant'}]