Theophylline ethylenediamide is administered to a client with COPD. The nurse knows that the medication is for which of the following purpose

A. To reduce bronchial secretions.
B. To relax bronchial smooth muscle.
C. To strengthen myocardial contractions.
D. To decrease alveolar elasticity.

任何物体均可以看成是由（）基本体组合而成。