Step 1: Concept
Bronchial asthma is characterized by bronchoconstriction, which can be relieved by stimulating Beta2-adrenergic receptors in the lungs.
Step 2: Meaning
Beta2 agonists cause relaxation of bronchial smooth muscle.
Step 3: Analysis
Montelukast is a leukotriene antagonist and Theophylline is a methylxanthine. Salbutamol (Albuterol) is a short-acting, selective Beta2 agonist used widely for the quick relief of asthma symptoms.
Step 4: Conclusion
Salbutamol is the most common Beta2 agonist used for bronchial asthma.
Final Answer: (A)