This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Lining of common bile duct \nSelect and explain. \nA. Simple columnar, B. Ciliated columnar, C. Pseudo stratified squamous, D. Transitional', 'role': 'user'}, {'content': "Answer: A \nExplanation: Common bile duct is lined by simple columnar epithelium , simple cuboidal epithelium at it's proximal region. Ref: IB Singh textbook of histology 6e pg 268.", 'role': 'assistant'}]