Answer:
A. By increasing the number of beta-adrenergic receptors
Step-by-step explanation:
Based on the scenario being described within the question it can be said that this drug achieves a therapeutic effect by increasing the number of beta-adrenergic receptors . This drug increases the amount of beta-adrenergic receptors while at the same time increasing or restoring beta receptor response to beta-adrenergic bronchodilating drugs.