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: Consider Input: Question: In the determination of water hardness due to the presence of Ca2 + and Mg2 + ions, the titrant reagent is used: 
 Options:  <1> Methyl orange. <2> A standard solution of potassium chloride. <3> Black Eriochrome T. <4> A standard solution of ethylenediaminetetraacetic acid (EDTA). <5> A solution of AEDT previously standardized against a solution of potassium phthalate.

Output: 4


Input: Consider Input: Question: What group of amino acids, when they are part of the proteins, can be phosphorylated? 
 Options:  <1> Val, Ser, Thr. <2> Phe, Ala, Gly. <3> Val, Glu, Asp. <4> Tyr, Ser, Thr. <5> Lys, Ser, Ile.

Output: 4


Input: Consider Input: Question: What characteristics increase the reliability of the psychophysiological evaluation? 
 Options:  <1> The law of initial values. <2> The autonomic balance and homeostasis. <3> The latency and duration of the answers. <4> The control of environmental artifacts and the organism. <5> The reactivity


Output: 4