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
[{'content': 'True about interstitial fibrosis -a) FVC↓b) FEV1/FVC normal or increasedc) FRC normald) FEV1/FVC ↓ \nSelect and explain. \nA. ac, B. a, C. ad, D. ab', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]