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': 'Best heat test agent for pulp testing: \nSelect and explain. \nA. GP sticks., B. Rubber wheel., C. Barlew disk., D. Rotation friction heat.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]