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': 'The floor of the occlusal rest is: \nSelect and explain. \nA. Ledge shaped, B. Half pear shaped, C. Spoon shaped, D. Half moon shaped', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]