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': 'Preservation of illioinguinal nerve is an important step in inguinal hernia operation while - \nSelect and explain. \nA. Incising the sub-cutaneous tissue, B. Incising the extra oblique aponeurosis, C. Incising the cremasteric fascia, D. Isolating the sac', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]