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
What is the function of the following armamentarium? 
Select and explain. 
A. Field isolation, B. Dental extraction, C. Crimping of stainless steel crown, D. Orthodontic wire bending
A: Field isolation
Answer: A: Field isolation 
Explanation: The figure shows rubber dam, which is used for isolation in oral cavity.
It was invented by S.C Barnum – 1864.
It has following parts:

Sheet
Rubber Dam Frame
Rubber Dam Clamp/Retainer
Rubber Dam Punch
Rubber Dam Forceps
Rubber Dam Lubricant
Rubber Dam Napkin
Anchors