The respiratory portion of the lung contain:

A、Pulmonary alveolus, alveolar duct, alveolar sac and bronchiole;
B、Respiratory bronchiole, alveolar duct, alveolar sac and pulmonary alveolus;
C、Pulmonary alveolus, alveolar duct, terminal bronchiole and Respiratory bronchiole;
D、Aveolar duct, alveolar sac, bronchiole and Respiratory bronchiole;
E、Pulmonary alveolus, alveolar duct, alveolar sac and terminal bronchiole