Which of the following criteria is used to diagnose chronic obstructive pulmonary disease (COPD)?
A) Productive cough for more than 3 months in the past year
B) Forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) <0.7
C) Peak expiratory flow rate (PEFR) <80% of predicted
D) Decreased diffusion capacity for carbon monoxide (DLCO)