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'.
Input: Question: The denaturation of proteins: 
 Options:  <1> It is accompanied by the loss of their activity. <2> It supposes the rupture of peptide bonds. <3> It is always an irreversible process. <4> Alter its primary structure. <5> It is carried out by chaperone proteins.
Output:
1