This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
[{'content': 'Isthmus of thyroid gland corresponds to which tracheal rings? \nSelect and explain. \nA. 2-Jan, B. 4-Feb, C. 5-Apr, D. 6-May', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The thyroid gland lies against veebrae C5,C6,C7 and T1 embracing the upper pa of the trachea Each lobe extends from the middle of thyroid cailage to the fouh of fifth tracheal ring The isthmus extends from second to the fouh tracheal ring. Ref BDC volume3,6th edition pg 140', 'role': 'assistant'}]