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: The O antigen used in the classification of Gram negative bacteria corresponds to: 
 Options:  <1> The flagellar proteins. <2> Components of the capsule. <3> The peptidoglycan. <4> The polysaccharide of lipopolysaccharides. <5> Plasma membrane proteins.
