This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
[{'content': 'Highest incidence of pneumothorax occurs when branchial plexus is blocked by which route \nSelect and explain. \nA. Interscalene, B. Supraclavicular, C. Infraclavicular, D. Axillary', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The incidence of pneumothorax may be as high as to 6% when brachial plexus is blocked through supraclavicular route but founately most of these pneumothorax resolve by themselves without treatment. Supraclavicular brachial plexus block: cellulitis/abscess over the site of injection. Use caution in patients with poor pulmonary reserve, as a resultant pneumothorax may significantly worsen their respiratory status (example: known pneumonia on the contralateral side ref Robbins 9/e pg 456', 'role': 'assistant'}]