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
After an operation on femur bone, chest X-ray shows widespread mottling throughout the lung field like a snowstorm. It is diagnostic of 
Select and explain. 
A. Fat embolism, B. Shock lung, C. Bronchopneumonia, D. Atelectasis
A: Fat embolism
Answer: A: Fat embolism 
Explanation: A i.e. Fat embolsm