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 reactivity of various carbonyl groups is determined by their relative stability. The order of reactivity towards nucleophiles is: 
 Options:  <1> Amides> Esters> Ketones> Aldehydes. <2> Aldehydes> Ketones> Esters> Amides. <3> Amides> Ketones> Aldehydes> Esters. <4> Aldehydes> Esters> Ketones> Amides. <5> Amides> Ketones> Esters> Aldehydes.
