A 5-month-old previously healthy male infant presents to the ED with cough and dyspnea for 2 days and a temperature of (101.1°F) and has bilateral expiratory wheezing and subcostal retractions. Xray is shown below. What is the most common etiology of this patients symptoms?
A Adenovirus
B M. pneumoniae
C Parainfluenza virus
D RSV
E Staphylococcus aureus