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
True statement about upper half anal canal is: 
Select and explain. 
A. Insensitive to pain, B. Drained by superficial inguinal lymph node, C. Lined by squamous epithelium, D. Supplied by superior mesentric aery
A: Insensitive to pain
Answer: A: Insensitive to pain 
Explanation: A i.e. Insensitive to pain