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
Three radiographs of the same tooth, taken using a digital intra-oral X-ray system, an intensifying screen/film cassette combination and conventional dental film (F speed). Which of the following X ray is taken with conventional dental film? 
Select and explain. 
A. A, B. B, C. C, D. All of the above
C: C
Answer: C: C 
Explanation: None