Definition: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: In an electrochemical cell, the supporting electrolyte serves to:
Options: <1> That the principle of electroneutrality in the dissolution is fulfilled. <2> That their ions are electrolized preferably in order to prevent the consumption of electroactive substance. <3> That in the cell there is transport by migration, in order to achieve greater sensitivity. <4> That the solution has an adequate electrical conductivity. <5> Encourage transport by diffusion of the electroactive substance.
Output:
4