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': 'RPI stands for: \nSelect and explain. \nA. Occlusal rest, proximal plate, I bar, B. Cingulum rest, proximal plate, I bar, C. Rest, proximal guide plane, I bar, D. Rest, proximal plate, indirect retainer', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]