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
In Teletherapy setup all are used except 
Select and explain. 
A. Irridium-191, B. Co - 60, C. Simulator, D. Computer
A: Irridium-191
Answer: A: Irridium-191 
Explanation: A i.e. Irridium 191