**Core Concept**
Leukotriene (LT) antagonists are a class of medications used in the management of asthma and allergic rhinitis. They work by blocking the action of leukotrienes, which are pro-inflammatory mediators involved in the pathophysiology of asthma.

**Why the Correct Answer is Right**
Leukotriene antagonists, such as montelukast, work by selectively blocking the cysteinyl leukotriene receptor 1 (CysLT1), which is responsible for mediating the pro-inflammatory effects of leukotrienes. By blocking this receptor, LT antagonists reduce the constriction of airway smooth muscle, decrease mucus production, and inhibit the recruitment of inflammatory cells to the airways. This results in improved lung function and reduced symptoms in patients with asthma.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because LT antagonists do not work by inhibiting the enzyme phospholipase A2 (PLA2), which is involved in the production of arachidonic acid, a precursor to leukotrienes. While PLA2 inhibitors may be useful in certain inflammatory conditions, they are not the mechanism of action of LT antagonists.
**Option B:** This option is incorrect because LT antagonists do not work by blocking the action of histamine, a key mediator of allergic inflammation. Histamine receptor antagonists, such as antihistamines, are a different class of medications used to treat allergic conditions.
**Option C:** This option is incorrect because LT antagonists do not work by inhibiting the enzyme cyclooxygenase (COX), which is involved in the production of prostaglandins, another class of pro-inflammatory mediators.

**Clinical Pearl / High-Yield Fact**
It's worth noting that LT antagonists are not bronchodilators and do not provide immediate relief of asthma symptoms. They are best used as add-on therapy to inhaled corticosteroids (ICS) and are most effective in patients with mild to moderate persistent asthma.

**Correct Answer:** C.