This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fundamentals in Radiology, Subject name: Radiology
[{'content': 'The intensity of colour in Doppler is determined by- \nSelect and explain. \nA. Direction flow, B. Velocity of flow, C. Strength of returning echo, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The intensity of colour in Doppler is determined by magnitude of the Doppler shift The magnitude of the Doppler shift is propoionate to the blood flow velocity and the Doppler angle Ref : Introduction to Vascular Ultrasonography 6th Edition Pg : 63', 'role': 'assistant'}]