An 82-year-old woman presents to the office with a 1-year history of worsening cough and shortness of breath. She has a 45 pack-year history of cigarette smoking and quit smoking 15 years ago. Vital signs reveal: <image 1>. ECG findings are normal. Her FEV1/FVC ratio is 65% of predicted. The most appropriate inhaled medication for this patient works by blocking which of the following receptors?
['$\\beta $1-adrenergic receptors', 'glucocorticoid receptors', 'histamine H1 receptors', 'leukotriene receptors', 'muscarinic receptors']