The correct answer is Promise.race(). This method takes an iterable of promises and returns a new promise that settles as soon as one of the input promises resolves or rejects. It's useful when you want to perform an action as soon as any of several asynchronous tasks completes.

To prevent the browser from freezing during a long-running while loop, you should use asynchronous code and setTimeout to break the loop into smaller chunks. This allows the browser to handle other tasks and prevents the UI from becoming unresponsive. This approach follows the principles of non-blocking and responsive UI in web development.

The concept of creating a single function or method that can operate on multiple types of objects is known as "Polymorphism." In JavaScript, polymorphism can be achieved through method overriding and dynamic method binding, enabling different objects to respond to the same method in a way that suits their specific type.

CORS (Cross-Origin Resource Sharing) is the API that allows you to make non-simple requests (such as those with custom headers or methods) to another domain in JavaScript while considering the Same-Origin Policy. XMLHttpRequest is an older alternative but has limitations compared to CORS. JSONP is a workaround technique, not an API, and WebSocket is used for full-duplex communication, not for cross-origin requests.

To manage successive data retrieval operations in a clean and maintainable manner, you can use the "Async/Await" approach in JavaScript. Async/Await simplifies asynchronous code and makes it look more like synchronous code, which can significantly enhance code readability and maintainability. It allows you to write asynchronous code in a more sequential style, making it easier to handle multiple asynchronous operations.

The common problem addressed by using asynchronous code in JavaScript is the avoidance of blocking the main thread. Blocking the main thread can lead to unresponsive user interfaces, making the application seem slow or frozen. Asynchronous code helps prevent this issue by allowing non-blocking execution of tasks.

Brendan Eich is credited as the main developer behind JavaScript's creation. He created JavaScript while working at Netscape Communications in 1995. His contributions to the language's design and development have had a lasting impact on web development.

o add elements to an array at a specific index in JavaScript, you would typically use the splice() method. The splice() method allows you to specify the index where you want to add elements and the number of elements to remove (if any). This method can be used for both adding and removing elements at a specific position in an array. For example, myArray.splice(2, 0, 'newElement') would add 'newElement' at index 2 of myArray.

In JavaScript classes, the constructor keyword is used to define the constructor method. This constructor method is automatically called when you create a new object from the class. It is used to initialize the object's properties and perform any setup required.

A while loop is the most suitable option for this scenario. It allows continuous checking of the player's score without the need for a fixed number of iterations. The condition in the while loop can be based on the score threshold, ensuring players progress to the next level when their score is below the threshold. The other options do not provide a continuous loop structure required for this task.

When you use arr.push(x), it appends the element x to the end of the array and increases the length property of the array by 1. Therefore, the new element will be at the index arr.length - 1, which is one less than the new length. For example, if arr has a length of 5, arr.push(x) will add x at index 4.

Lexical scoping in JavaScript refers to the way variable scope is determined by the placement of variables in the source code. Variables declared inside a function are accessible within that function, creating a hierarchy of scope. This helps prevent variable conflicts and promotes clean code.