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 magnetic field in an MRI machine is measured in - \nSelect and explain. \nA. Housefield units, B. Tesla, C. MHz, D. None', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Strength of magnetic field used in MRI is measured by Telsa units CT attenuation values are measured by Hounsfield units. Frequency of sound waves used in USG are measured by MHz', 'role': 'assistant'}]