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
[{'content': 'The following are true of haemorrhoids except - \nSelect and explain. \nA. They are arteriolar dilatations, B. They are common causes of painless bleeding, C. They cannot be per rectally palpated, D. They can be banded', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]