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
[{'content': 'What is true about sinus venosus- \nSelect and explain. \nA. Forms rough wall of right atrium, B. Forms smooth wall of right atrium, C. Forms right coronary sinus, D. Forms left leaflet of coronary sinus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]