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: Dental
[{'content': 'Which of the following maxillary major connector provides the greatest retention: \nSelect and explain. \nA. Palatal strap., B. Complete palate., C. Double palatal bar., D. U shaped.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]