**Core Concept**
Long-acting beta-2 agonists (LABAs) are a class of bronchodilators that selectively activate beta-2 adrenergic receptors in the lungs, resulting in bronchodilation and relief of asthma symptoms. They are often used in combination with inhaled corticosteroids for the maintenance and control of asthma.

**Why the Correct Answer is Right**
The correct answer is a LABA that prolongs bronchodilation by binding to beta-2 adrenergic receptors on airway smooth muscle cells. This leads to increased levels of cyclic AMP, which inhibits airway smooth muscle contraction and results in bronchodilation. The correct answer is a well-known LABA used in the management of asthma and chronic obstructive pulmonary disease (COPD).

**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because it's a short-acting beta-2 agonist, which provides quick relief but has a shorter duration of action compared to LABAs.
* **Option B:** This is incorrect because it's an anticholinergic agent, which works by blocking muscarinic receptors and is not a LABA.
* **Option C:** This is incorrect because it's an inhaled corticosteroid, which reduces inflammation but does not provide bronchodilation.

**Clinical Pearl / High-Yield Fact**
LABAs should be used with caution in patients with asthma, as they can increase the risk of exacerbations and asthma-related deaths when used as monotherapy.

**Correct Answer:** C. Salmeterol. Salmeterol is a long-acting beta-2 agonist used in the management of asthma and COPD.