A child is brought to the emergency department struggling to breathe with a prolonged bronchospasm and severe hypoxemia. Assessment revealed the use of accessory muscles, a weak cough, audible wheezing sound, moist skin, and tachycardia. Which of the following is the most likely diagnosis?

a) Pulmonary embolism
b) Severe asthma attack
c) Chronic obstructive pulmonary disease
d) Cystic fibrosis