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: Pathology
[{'content': 'Salivary gland stone most commonly involves \nSelect and explain. \nA. Submandibular gland, B. Parotid gland, C. Sub lingual glands, D. Lingual glands', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]