Inhaled corticosteroids are generally used to:

Inhaled corticosteroids are primarily used to reduce airway inflammation, making this the correct choice. These medications work by targeting the underlying inflammation in the airways of individuals with respiratory conditions, such as asthma or chronic obstructive pulmonary disease (COPD). By decreasing inflammation, inhaled corticosteroids help to alleviate symptoms, improve airflow, and enhance the overall function of the respiratory system.

Controlling inflammation is crucial since increased airway inflammation can lead to narrowing, which ultimately causes symptoms such as wheezing, shortness of breath, and tightness in the chest. By maintaining low levels of inflammation, inhaled corticosteroids help prevent exacerbations and the need for rescue medications.

The other choices, while related to respiratory health, do not accurately reflect the primary action of inhaled corticosteroids. They do not primarily act to relax bronchial muscles; that function is typically managed by bronchodilators. They are not directly utilized for controlling bacterial infections, as antibiotics would be used for that purpose. Lastly, they don't clear mucus from the lungs; techniques and medications specifically targeting mucus clearance would be employed for that function.