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': 'Five factors of articulation were originally described by \nSelect and explain. \nA. Boucher, B. Fenn Lidlow and Gimson, C. Vincent Trapazzano, D. Rudolf Hanau', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]