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: Surgery
Pauvel's angle is 
Select and explain. 
A. Neck shaft angle of femur, B. The difference between neck shaft angle between two femurs of a patient, C. Formed by joining a line extended from fracture line of femur neck to an arbitrary line depicting the horizontal plane, D. None of the above
C: Formed by joining a line extended from fracture line of femur neck to an arbitrary line depicting the horizontal plane
Answer: C: Formed by joining a line extended from fracture line of femur neck to an arbitrary line depicting the horizontal plane 
Explanation: C i.e. Formed by joining a line extended from fracture line of femur neck to an arbitrary line depicting the horizontal plane