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
Radiation exposure is least in 
Select and explain. 
A. CT pelvis, B. IVP, C. Cystography, D. Micturating cysto - Urethrogram
D: Micturating cysto - Urethrogram
Answer: D: Micturating cysto - Urethrogram 
Explanation: MCU : 1 - 2 (msv) - 60 chest x - ray.
Cystography : 1- 8 (msievert) - 90cxr.
IVP : 2 - 4 - 120cxr.
CT pelvis : 10 - 500cxr.