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: Surgery
Excision of the submandibular gland for calculus or tumours is done by incision below angle of the jaw. Special care should be taken to avoid which nerve? 
Select and explain. 
A. Ansa cervicalis, B. Mandibular branch of facial nerve, C. Posterior auricular nerve, D. Submandibular ganglion
B: Mandibular branch of facial nerve
Answer: B: Mandibular branch of facial nerve 
Explanation: None