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
Upper border of posterior belly of digastric is related to: 
Select and explain. 
A. Posterior auricular artery., B. Occipital artery., C. Ascending pharyngeal artery., D. Lingual artery.
A: Posterior auricular artery.
Answer: A: Posterior auricular artery. 
Explanation: The upper border of posterior belly of digastric is related to "posterior auricular artery" while its lower border is related to "occipital artery".