This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Monitoring in Anesthesia, Subject name: Anaesthesia
All are indication of evoked potential monitoring except:- 
Select and explain. 
A. Cerebral tumor resection, B. Brachial plexus repair, C. Mastoid surgery, D. Spinal fusion and instrumentation
C: Mastoid surgery
Answer: C: Mastoid surgery 
Explanation: Indications for intraoperative monitoring of evoked potential include surgical procedures with possible neurological insult. 1. Spinal fusion & instrumentation 2. Spine & spinal cord tumor resection 3. Brachial plexus repair 4. Thoracoabdominal aoic aneurysm repair 5. It also facilitate probe localization during stereotactic surgery