**Core Concept**
β-agonists are a class of medications used to treat asthma by stimulating **β2-adrenergic receptors** in the lungs, leading to bronchodilation. This mechanism helps to relieve bronchospasm and improve airflow. The underlying principle involves the relaxation of airway smooth muscle.

**Why the Correct Answer is Right**
The correct answer is related to the mechanism of action of β-agonists, which includes increasing intracellular **cyclic AMP (cAMP)** levels by stimulating **adenylyl cyclase**, leading to the relaxation of smooth muscle cells. This action is mediated through the activation of **β2-adrenergic receptors**. However, the question is incomplete, so we'll proceed with general knowledge of β-agonists in asthma.

**Why Each Wrong Option is Incorrect**
**Option A:** This choice is potentially incorrect because β-agonists do act by stimulating β2-adrenergic receptors, which is a well-known mechanism.
**Option B:** This could be incorrect if it suggested a mechanism not involving β2-adrenergic receptors or bronchodilation.
**Option C:** Similarly, this might be wrong if it proposed an action unrelated to the known effects of β-agonists on airway smooth muscle.
**Option D:** Without the specific text, we can't directly address why this is incorrect, but typically, β-agonists are not known for mechanisms outside of β2-receptor stimulation and subsequent bronchodilation.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that β-agonists, particularly short-acting β-agonists (SABAs), are used for quick relief of asthma symptoms, while long-acting β-agonists (LABAs) are used for long-term control, often in combination with **inhaled corticosteroids**.

**Correct Answer:** Correct Answer: D. Decreasing histamine release.