This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
Maximum Radiation exposure occurs from: 
Select and explain. 
A. Bone scan, B. CT scan, C. X-ray, D. All of the above
A: Bone scan
Answer: A: Bone scan 
Explanation: Radiation Exposure:
Bone scan > CT scan > X-ray (But MRI given in option, then it is the answer).