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 a determination of the activity of an enzyme, the depletion of the substrate: 
 Options:  <1> It is essential for most trials. <2> It may give falsely low results in sera with high enzymatic activity. <3> It occurs when the reagent is finished. <4> It occurs due to a defect in the spectrophotometer. <5> It can lead to falsely elevated results in sera with high enzymatic activity.
