Which of the following is NOT a core Web Services API call?

The correct answer is "clone()" because it is not considered a core call in the Salesforce Web Services API. The core API calls primarily include operations that allow for the creation, retrieval, updating, and deletion of records, which are encapsulated in the create(), delete(), and search() functions.

The create() function is used to insert records into Salesforce, the delete() function removes records, and the search() function allows querying of records based on specified criteria.

In contrast, the clone() function is specific to certain user interface operations and is not part of the foundational API operations typically utilized for integrating with Salesforce. The absence of clone() in core API calls emphasizes its limited usage, primarily for user operations rather than programmatic integration, distinguishing it from the main CRUD (Create, Read, Update, Delete) operations that are essential in API interactions.