Question: In a patient with asthma symptoms, diagnostic confirmation of the disease will be made first by: 
 Options:  <1> The finding of a reversible obstruction of air flow in spirometry. <2> A positive allergic skin test. <3> An increase in the number of eosinophils in the induced sputum. <4> The elevation of nitric oxide in exhaled air (FENO). <5> The presence of a specific IgE in blood to an aeroallergen.
1