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
Ionization radiation acts on tissue leading to 
Select and explain. 
A. Linear acceleration injury, B. Excitation of electron from orbit, C. Formation of pyramidine dimer, D. Thermal injury
B: Excitation of electron from orbit
Answer: B: Excitation of electron from orbit 
Explanation: B i.e. Excitation of electron from orbit