Step 1: Concept
Leukotrienes are inflammatory chemicals the body releases when an allergen is inhaled, causing airway constriction.
Step 2: Meaning
Leukotriene antagonists block these chemicals to prevent bronchoconstriction and inflammation in the lungs.
Step 3: Analysis
Drugs like Montelukast and Zafirlukast are used primarily for the long-term management and prophylaxis of bronchial asthma. They are not used for acute relief but help maintain open airways.
Step 4: Conclusion
The primary therapeutic application for leukotriene antagonists is the treatment of Asthma.
Final Answer: (A)