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: Dental
To observe a recurrent caries under a class II amalgam restoration, vertical angulation of the central Xrays should be 
Select and explain. 
A. Perpendicular to the film placed, B. Perpendicular to theocclusal surface of the tooth, C. Parallel to the buccolingual plane of gingival surface of restoration, D. Perpendicular to the cavosurface bevels in the proximal box
C: Parallel to the buccolingual plane of gingival surface of restoration
Answer: C: Parallel to the buccolingual plane of gingival surface of restoration 
Explanation: None