You will be given a definition of a task first, then some input of the task.
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'.

Question: The chemistry of diazonium salts provides the main synthetic method for preparing aryl fluorides by a process called:
Options: <1> Reorganization of Claisen. <2> Gabriel's reaction. <3> Diazotization reaction. <4> Sandmeyer reaction. <5> Schiemann reaction.
Output:
5