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
Plunging ranula is ? 
Select and explain. 
A. Cystic growth of sublingual gland, B. Lymph node, C. A tumor in floor of mouth, D. None
A: Cystic growth of sublingual gland
Answer: A: Cystic growth of sublingual gland 
Explanation: Plunging ranula:
• Extravasation cyst of sublingual salivary gland
• Cause: trauma or obstruction of duct/glandular tissue
• The cyts plunges into the submandibular region by dissecting between the fascial planes and the fllor mouth (mylohoid)