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
Referred pain in external haemorrhoids is due to - 
Select and explain. 
A. Common pudendal nerve, B. Inferior rectal nerve, C. Splanchnic nerve, D. Sympathetic nerve
B: Inferior rectal nerve
Answer: B: Inferior rectal nerve 
Explanation: Pain sensation below the pectinate line is carried by inferior rectal nerve, a branch of pudendal nerve.