An Adult Develops Chronic Cough with Episodes of Wheezing and Shortness

An adult develops chronic cough with episodes of wheezing and shortness of breath. The provider performs chest radiography and other tests and rules out infection, upper respiratory, and gastroesophageal causes. Which test will the provider order initially to evaluate the possibility of asthma as the cause of these symptoms?

A) Allergy testing
B) Methacholine challenge test
C) Peak expiratory flow rate (PEFR)
D) Spirometry