72. 下列關於 COPD 的致病機轉，下列何者不是： (A) The major site of airflow limitation is the small conducting airway (＜2mm in diameter) (B) Lung express TH1 cytokines including interferon-y、CCR6 and CXCR4. (C) IL-1β play a role in the development of emphysema (D) Histone deacetylase(HDAC) 2 has been shown to be reduced in lung cells of subjects with COPD.