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
The magnetic field in an MRI machine is measured in - 
Select and explain. 
A. Housefield units, B. Tesla, C. MHz, D. None
B: Tesla
Answer: B: Tesla 
Explanation: 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