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': 'Which mode of ultrasound help is Orbital biometry? \nSelect and explain. \nA. A- mode, B. B-mode, C. M-mode, D. D-mode', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A Mode Ultrasound is Amplitude Mode used for measuring Axial length of Eyeball and Orbital Biometry. A scan in Opthalmology is the A Mode Ultrasound. B mode is used in routine ultrasonography. M mode is used in chest and obstetric USG. D mode is used for vessels.', 'role': 'assistant'}]