This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
[{'content': 'Root value of thoracodorsal nerve \nSelect and explain. \nA. C5,C6,C7, B. C6,T1, C. C6,C7,C8, D. T1,T2', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Thoracodorsal nerve or long thoracic nerve arises from brachial plexus. Its nerve value is C5, C6 and C7. REF:BDChaurasia 7th edition Page no: 57.', 'role': 'assistant'}]