This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: ULTRASOUND, Subject name: Radiology
[{'content': 'Thyroid malignancies appear on USG as \nSelect and explain. \nA. Hypoechoic, B. Anechoic, C. Hyperechoic, D. Isoechoic', 'role': 'user'}, {'content': 'Answer: A \nExplanation: On sonography, thyroid tumors are solid,hypoechoic masses.', 'role': 'assistant'}]