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 oxygen we consume in the respiratory chain is transformed into: 
 Options:  <1> Acetyl-CoA. <2> Carbon dioxide. <3> Carbon monoxide. <4> Water. <5> Carbonic acid.
