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
[{'content': 'The proximal fragment of scaphoid after fracture is predisposed for Avascular Necrosis because: \nSelect and explain. \nA. Retrograde blood flow to the proximal fragment, B. Difficulty in immobilizing the proximal fragment, C. Fracture configuration of the proximal fragment is usually comminuted, D. Proximal Fragment aiculates with the radius', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Retrograde blood flow to the proximal fragment', 'role': 'assistant'}]