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
DMFT index in 1938 was not developed by: 
Select and explain. 
A. Dean H.T., B. Henry T. Klein, C. Knutson J.W., D. Carole E. Palmer
A: Dean H.T.
Answer: A: Dean H.T. 
Explanation: None