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
[{'content': 'Upper border of thyroid cartilage is at - \nSelect and explain. \nA. C2, B. C4, C. C6, D. Tl', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Thyroid cartilage, itself lies in front of C4 - C5 level. Its upper border is at C4 vertebra level.\n\n"The superior border of the thyroid cartilage is at the C4 level." — Atlas of anatomy', 'role': 'assistant'}]