This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
[{'content': 'Which is a typical intercostal nerve? \nSelect and explain. \nA. 1st, B. 3rd, C. 7th, D. 9th', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 3rd * Ventral rami of upper 11th thoracic spinal nerves are known as intercostal nerves and ventral ramus of T12 is known as subcostal nerve.* Upper six intercostal nerves supply thoracic wall whereas lower five intercostal nerves and subcostal nerve supply thoracic and anterior abdominal walls and hence known as thoracoabdominal nerves.* Upper two intercostal nerves also supply the upper limb. Thus only 3rd to 6th are called typical intercostal nerves.", 'role': 'assistant'}]