This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nuclear medicine, Subject name: Radiology
Radioisotopes emit all the following except? 
Select and explain. 
A. Alpha Rays, B. Beta Rays, C. Gamma Rays, D. X-rays
D: X-rays
Answer: D: X-rays 
Explanation: X rays are aificially produced in the Xray tube or by using LINAC(Linear Accelerator) Radioisotopes emit either Alpha Rays,Beta Rays and Gamma Rays