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: Medicine
Bibasilar Velcro crackles occur in ? 
Select and explain. 
A. Acute pulmonary oedema, B. Acute bronchopneumonia, C. Pulmonary fibrosis, D. Pulmonary embolism
C: Pulmonary fibrosis
Answer: C: Pulmonary fibrosis 
Explanation: None