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: Surgery
[{'content': 'Plunging ranula is ? \nSelect and explain. \nA. Cystic growth of sublingual gland, B. Lymph node, C. A tumor in floor of mouth, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Plunging ranula:\n• Extravasation cyst of sublingual salivary gland\n• Cause: trauma or obstruction of duct/glandular tissue\n• The cyts plunges into the submandibular region by dissecting between the fascial planes and the fllor mouth (mylohoid)', 'role': 'assistant'}]