Asthma USMLE Step 1 Practice Question

A 45-year-old woman with newly diagnosed asthma presents for evaluation of recurrent symptoms over the past 2 months. She reports wheezing and dyspnea triggered by exposure to air conditioning, spring pollen, and her cat at home. Symptoms occur approximately 2-3 times per week and occasionally wake her from sleep once monthly. She uses albuterol inhaler 2-3 times weekly and reports no systemic corticosteroid use. Vital signs are stable with SpO2 98% on room air. Spirometry shows FEV1 82% predicted with reversibility noted on bronchodilator testing. Chest examination reveals end-expiratory wheeze bilaterally. Which of the following is the most appropriate initial controller medication for this patient?