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': 'Structures lying deep to posterior belly of digastric are all except - \nSelect and explain. \nA. Retromandibular vein, B. Hypoglossal nerve, C. Hyoglossus muscle, D. Occipital artery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]