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': 'Purely serous gland among the following: \nSelect and explain. \nA. Parotid gland, B. Submandibular gland., C. Sublingual gland., D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]