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: Pathology
Dark radiolucent shadows appearing at the neck of teeth, most obvious on the mesial and distal aspect: 
Select and explain. 
A. Radiation caries, B. Rampant caries, C. Early childhood caries., D. None of the above
A: Radiation caries
Answer: A: Radiation caries 
Explanation: None