This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
[{'content': 'Spiral valve of Heister is seen in \nSelect and explain. \nA. Neck of gall bladder, B. Cystic duct, C. Colon, D. Pylorus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Spiral valves of Heister are undulating folds or valves in the proximal mucosa of the cystic duct. The cystic duct attaches the gallbladder to the common bile duct. The spiral valves of Heister are suppoed by underlying smooth muscle fibers. ref -eahslab.com', 'role': 'assistant'}]