The patient is a 3-month-old infant who suddenly developed cyanosis and audible expiratory wheezing. Retractions and nasal flaring with a respiratory rate of 80/minute are present. The patient's mother reports that he has had a mild cold with a cough for two or three days. The patient has had a low-grade fever. There is no family history of asthma or allergies. The initial treatment of choice for

this patient would be:

a. epinephrine 1:1000 subcutaneous.
b. humidified oxygen.
c. nebulized racemic epinephrine.
d. immediate endotracheal intubation.

b