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 the chronic obstructive pulmonary disease (COPD) \nSelect and explain. \nA. FEVI <30 of predicted value, B. FEV1/FVC<0.7, C. total lung capacity increased, D. All', 'role': 'user'}, {'content': 'Answer: D \nExplanation: In COPD, airflow obstruction is demonstrated by spirometry in which the post-bronchodilator FEV1/FVC is less than 70%. \nThe severity of COPD may be defined in relation to the post-bronchodilator FEV1 which is <30% predicted in very severe type. \nMeasurement of lung volumes provides an assessment of hyperinflation.COPD is characterised by an increase in residual volume, residual volume/total lung capacity ratio, and progressive hyperinflation(increased total lung capacity) late in the disease.', 'role': 'assistant'}]