Task: Question Answering
Input (English): Question: The quality of a spectrum can be defined: 
 Options:  <1> Based on the relationship between the intensities of the bands containing information (S) and noise (R). <2> Based on the selected wavelength. <3> Only in function of the analytical signal. <4> Depending on the relationship between wavelength and noise. <5> Based on very low frequency noise.
Output (English): 1