This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
Radiotherapy works by 
Select and explain. 
A. Coagulation proteins, B. Necrosis of cells, C. Ionization of tissues, D. None of the above
C: Ionization of tissues
Answer: C: Ionization of tissues 
Explanation: Radiation therapy works by damaging the genetic material within cancer cells and limiting their ability to successfully reproduce. When these damaged cancer cells die, the body naturally eliminates them.Radiation therapy is based on the principle that ionizing radiation kills proliferating cells(Refer: Thayalan's Basic Radiological Physics' 1st edition, pg no: 206-207)