How is a promise created in JavaScript?

A promise in JavaScript is created using the Promise constructor, which requires an executor function as an argument. This constructor takes a function that has two parameters, usually called resolve and reject. The executor function is executed immediately by the Promise implementation, and from within this function, you can determine when to call resolve or reject based on the outcome of an asynchronous operation.

The resolve function is called when the operation completes successfully, and the promise transitions to the fulfilled state. Conversely, if the operation fails, the reject function is called, which transitions the promise to the rejected state. This mechanism enables better management of asynchronous tasks, allowing you to attach success and failure handlers later using methods like .then() and .catch().

Thus, the correct understanding of promise creation focuses on the necessity of an executor function within the Promise constructor, hence why this is the right choice. Other options do not accurately reflect the method and structure needed to create a promise in JavaScript.