Detailed Instructions: 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'.
Problem:Question: A coulometric evaluation:
Options: <1> You do not need the current performance to be 100%. <2> It does not need an indicator system of the end point. <3> Always use a potentiostatic system. <4> It uses a titrant that is generated electrolytically. <5> You need a burette to add the titrant.
Solution:
4