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 reaction of Diels Alder is an example of reaction: 
 Options:  <1> Concerted and stereospecific. <2> Nucleophilic substitution of order 2. <3> Nucleophilic substitution of order 1. <4> Condensation polymerization. <5> Nucleophilic addition.
