Instructions: 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 an alkene with metachloroperbenzoic acid causes a cyclic ether which is called: 
 Options:  <1> Furano <2> Dioxane <3> Epoxide <4> Azirano <5> Lactone
Output:
3