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
K Flex file is 
Select and explain. 
A. Made of triangular blank, B. Made of square blank, C. Made of rhomboid blank, D. Made of round wires
C: Made of rhomboid blank
Answer: C: Made of rhomboid blank 
Explanation: None