Promises in JavaScript have a built-in mechanism for handling errors (rejected states). The standard and most robust way to handle a potential rejection in a promise chain is to append a .catch() handler. This handler will be executed if the promise at any point in the preceding chain is rejected. It provides a clean, readable, and asynchronous-safe way to centralize error handling for the promise-based operation. Using .catch() ensures that both network errors from the request and runtime errors within any preceding .then() callbacks are gracefully handled.

A. A try/catch block only works for synchronous code. It will not catch a rejection that occurs asynchronously inside the .then() callback of a promise.

B. This is a duplicate of option A and is incorrect for the same reason.

D. The .finally() handler is executed whether the promise is fulfilled or rejected. It is intended for cleanup code, not for handling the error itself.

1. Mozilla Developer Network (MDN). Promise.prototype.catch(). Section: "Description". This document explicitly states that .catch() is used for handling errors in promise chains and is syntactic sugar for .then(null, onRejected).

2. Mozilla Developer Network (MDN). Using Promises. Section: "Chaining". This guide demonstrates the proper use of .then() and .catch() for successful promise resolution and error handling.

3. Mozilla Developer Network (MDN). Promise.prototype.finally(). This document clarifies that .finally() is for code that should run regardless of the promise's outcome and is not for handling the rejected value.