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
While taking the bitewing film, the dentist should keep the direction and angulations of central ray: 
Select and explain. 
A. 10° below the horizontal plane, B. 10° above the horizontal plane, C. 10° to the right, D. 10° to the left
B: 10° above the horizontal plane
Answer: B: 10° above the horizontal plane 
Explanation: The aiming cylinder is positioned about +10 degrees to project the beam parallel with the occlusal plane (occlusal dentinoenamel junction). This orientation minimises the overlapping of the opposing cusps onto the occlusal surface and thus improves the probability of detecting early occlusal lesions at the dentinoenamel junction.
Ref: ORAL RADIOLOGY Principles and Interpretation,Stuart C. White,Michael J. Pharoah Edition 7 page no 114