Solution

In AJAX, setting the async property to true allows JavaScript code to execute without waiting for the response from the server, enabling asynchronous communication. This approach prevents the browser from "blocking" or pausing the script's execution, thus improving user experience by allowing other interactions to continue while waiting for the server's response. By default, most AJAX requests are asynchronous (async = true), making web applications more responsive and efficient. Asynchronous operations are critical for modern web development, especially in single-page applications (SPAs), where responsiveness is key. If async were set to false, the browser would behave synchronously, waiting for the server’s response before executing subsequent code, which can lead to significant delays in user experience, especially with slow network connections. Option A (method) - This property specifies the HTTP method (e.g., GET, POST) used in the request, not the asynchronous behavior. Option B (readyState) - This property holds the current state of the XMLHttpRequest but does not control whether the request is asynchronous. Option D (status) - The status property represents the HTTP status code of the server’s response (like 200 for success), not the asynchronous nature of the request. Option E (responseText) - responseText holds the data returned from the server but does not control whether the request waits for the response.