Task: Text Categorization
Input (English): Question: In certain cases it is necessary to carry out previous treatments with oxidizing or reducing agents in redox evaluations in order to: 
 Options:  <0> Transform the analyte to an adequate oxidation state for subsequent evaluation. <1> Ensure that all the analyte is in solution. <2> Prepare the indicator solution so that it correctly rotates at the end point. <3> Make the reaction between titrator and analyte complete. <4> Improve the accuracy of the assessment.
Output (English): pharmacology