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: Anatomy
[{'content': 'Sternocleidomastoid muscle is supplied by: \nSelect and explain. \nA. Vagus nerve, B. Spinal accessory nerve, C. Marginal mandibular branch of facial nerve, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The spinal accessory nerve provides the motor supply. It passes through the muscle.\nThe spinal\xa0accessory\xa0nerve supplies:\n\nThe sternocleidomastoid, the chin turning\nThe trapezius,\xa0the shrugging muscle.\n\nCervical nerves provide a proprioceptive sensations to these muscles.\nReference: B D Chaurasia’s Head and Neck anatomy, 6th ed page no 384', 'role': 'assistant'}]