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 type of wire formed by twisting five tempered wire over a common wire? 
Select and explain. 
A. Twisted wire, B. Braided wire, C. Axial wire, D. Co-axial wire
D: Co-axial wire
Answer: D: Co-axial wire 
Explanation: Coaxial Archwire
Coaxial archwires are made of a central core wire of 0.006 inch diameter wire with 5 or 6 outer wires. 
These wires are more flexible and were very frequently used for initial alignment of the teeth before the advent of Ni-Ti wires.
Textbook of  Orthodontics Gurkeerat Singh 2nd ed pg no 335