This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Orthopaedics
The given below instrument is used for: 
Select and explain. 
A. For cutting ribs in spinal surgery, B. For smoothening of the edges in amputation surgery, C. Used as nibbler and remove fibrous tissue from non-union site, D. To hold the hard tissues
C: Used as nibbler and remove fibrous tissue from non-union site
Answer: C: Used as nibbler and remove fibrous tissue from non-union site 
Explanation: Ans. (c) Used as nibbler and remove fibrous tissue from non-union siteRef: Textbook of Orthopedics 4th Ed by John Ebnezar; Page No- 861* It is a Double-action bone nibbler (Rounger). The double- action nibblers are mechanically superior.* Bone nibbler is available in various sizes and with different angle of the nose.# Curved nibbler - use for spinal surgery# Straight nibbler -general use# Double action nibbler - straight or curved.