Task: Question Answering
Input (English): Question: The gas used to generate the ICP plasma (coupled induction plasma) is: 
 Options:  <1> Hydrogen for being diatomic, chemically inert and with a low ionization energy. <2> Oxygen because it is diatomic, highly reactive and with a high ionization energy. <3> Argon, being monatomic, chemically inert and with a high ionization energy. <4> Xenon, being monatomic, highly reactive and with a low ionization energy. <5> None of the above is correct, because the gas used is helium.
Output (English): 3