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': 'Submandibular gland is: \nSelect and explain. \nA. Pure serous., B. Pure mucous., C. Mixed and predominantly serous., D. Mixed and predominantly mucous.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]