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': 'Floor of posterior triangle of neck is formed by \nSelect and explain. \nA. Semispinalis capitis, elevator scapulae, scalenus anterior, scalenus medius, B. Levator scapulae, splenius capitis, scalenus medius, scalenus anterior, C. Semispinalis capitis, scalenus anterior, splenius capitis, sternocleidomastoid, D. Levator scapulae, scalenus posterior, semispinalis capitis,scalenus medius', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Muscles forming floor of posterior triangle of neck :\n\n\xa0Semispinalis capitis.\n\xa0Splenius capitis.\n\xa0Levator scapulae.\n\xa0Scalenus posterior.\n\xa0Scalenus medius.', 'role': 'assistant'}]