Final answer:
The common selective beta 2 adrenergic agonist is b. Albuterol, which is used to treat respiratory conditions by causing bronchial dilation.
Step-by-step explanation:
The common selective beta 2 adrenergic agonist from the given options is b. Albuterol. Selective beta 2 adrenergic agonists are medications that primarily stimulate beta 2 receptors, which are located in the lungs and are responsible for bronchial dilation. Albuterol is frequently used in the treatment of respiratory conditions like asthma and chronic obstructive pulmonary disease (COPD) to relax muscle bands that tighten around the airways, thereby opening them and making it easier for a patient to breathe. In contrast, Metoprolol and Atenolol are both beta 1 selective blockers, and Labetalol is a non-selective blocker that antagonizes both alpha and beta adrenergic receptors.