Which of the following best describes the pharmacological action of salbutamol?

Salbutamol is a selective beta-2 adrenergic agonist, primarily utilized in management of conditions like asthma and chronic obstructive pulmonary disease (COPD). Its primary pharmacological action is to relax bronchial smooth muscle, which leads to bronchodilation. This effect opens up the airways, improving airflow and alleviating symptoms of wheezing and shortness of breath associated with bronchospasm.

The other options do not accurately reflect the pharmacological action of salbutamol. Inhibiting mucus production, while potentially beneficial in some contexts, is not a direct action of salbutamol. Increasing white blood cell count and increasing peripheral resistance are actions that are unrelated to the therapeutic effects of salbutamol and correspond more to different types of drugs or physiological responses. The focus of salbutamol's action on the relaxation of bronchial smooth muscle makes it a critical agent in respiratory care.