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': 'For long span distal extension bases where rigidity is critical the major connector of choice is: \nSelect and explain. \nA. Palatal strap, B. Antero posterior palatal bar, C. Closed horse shoe, D. Horse shoe', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]