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
Five factors of articulation were originally described by 
Select and explain. 
A. Boucher, B. Fenn Lidlow and Gimson, C. Vincent Trapazzano, D. Rudolf Hanau
D: Rudolf Hanau
Answer: D: Rudolf Hanau 
Explanation: None