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: All components of the respiratory chain: 
 Options:  <1> They pump protons. <2> They exchange electrons. <3> They are high molecular weight complexes. <4> They are membrane proteins. <5> They are soluble.
