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
Radioactive element not used now-a-days in medical practice: 
Select and explain. 
A. Radium 226, B. Co60, C. Cs 137, D. Iridium 192
A: Radium 226
Answer: A: Radium 226 
Explanation: Ans. Radium 226