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': 'In the following arrangement, if  the rest is placed on a cantilever pontic , the cantilever can act as a \nSelect and explain. \nA. First class lever, B. Second class lever, C. Third class lever, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A cantilever can be described as a rigid beam supported only at one end. When force is directed against the unsupported end of the beam (as in this rest placed on a cantilevered pontic), the cantilever can act as a first-class lever. The mechanical advantage in this illustration favors the effort arm.', 'role': 'assistant'}]