This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
Calculi are most commonly seen in which salivary gland 
Select and explain. 
A. Minor salivary gland, B. Parotid, C. Submandibular, D. None
C: Submandibular
Answer: C: Submandibular 
Explanation: Eighty per cent of all salivary stones occur in the submandibular glands. Eighty per cent of submandibular stones are radio-opaque . Calculi are more common in submandibular gland because the gland secretion is viscous, contains more calcium and also its drainage(Whaon's duct) is nondependent, causing stasis. Secretion from parotid gland is serous, contains less calcium and so stones are not common. Reference : Bailey and Love's sho practice of surgery 27th edition , chapter 49 , pg no 780