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: Anaesthesia
Pneumothorax is a complication of 
Select and explain. 
A. Axillary block, B. Brachial plexus block, C. Epidural block, D. High Spinal block
B: Brachial plexus block
Answer: B: Brachial plexus block 
Explanation: B i.e. Brachial Plexus block Brachial plexus block with interscalene approach provides most intense anesthesia in C5-C7 dermatomes and least intense in C8-T1 (ulnar nerve) area.