Which of the following HTTP methods should be idempotent in nature?

In the context of HTTP methods, idempotence is a property that means an operation can be performed multiple times without changing the result beyond the initial application. The HTTP methods that should be idempotent are:

1. GET: Used to retrieve data from a server. Making the same GET request multiple times should return the same result.

2. HEAD: Similar to GET, but it retrieves headers instead of the body. It’s used for obtaining meta-information about the entity implied by the request without transferring the entity-body itself.

3. PUT: Used to update or replace the current representations of the target resource with the request payload. Repeatedly calling a PUT request with the same data will not change the outcome beyond the initial update or replacement.

4. DELETE: Used to delete a specified resource. Once a resource is deleted, repeating the DELETE request should have no further effect since the resource is already removed.

5. OPTIONS: This method is used to describe the communication options for the target resource. Repeatedly making OPTIONS requests should yield the same result, as it simply describes methods allowed by a resource.

These methods are designed to be idempotent to ensure reliability and predictability in web applications, allowing clients to repeat requests without concern over inadvertently causing changes or harmful effects.