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
Rubber dam was introduced by 
Select and explain. 
A. Tomy Hanks, B. S.C. Barnum, C. Hedstorm, D. G.V. Black
B: S.C. Barnum
Answer: B: S.C. Barnum 
Explanation: None