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
Purely serous gland among the following: 
Select and explain. 
A. Parotid gland, B. Submandibular gland., C. Sublingual gland., D. None
A: Parotid gland
Answer: A: Parotid gland 
Explanation: None