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: Anatomy
Isthmus of the thyroid gland is across tracheal ring - 
Select and explain. 
A. 2nd to fourth, B. 3rd to fifth, C. 5th and 6th, D. 4th only
A: 2nd to fourth
Answer: A: 2nd to fourth 
Explanation: The isthmus extends from the second to the fourth tracheal ring.