Which method is used to select an element in jQuery?

The method used to select an element in jQuery is the dollar sign function, represented as $(). This function allows for easy and efficient selection of HTML elements in the DOM. When you pass a selector string to $(), it returns a jQuery object containing the matched elements, making it straightforward to manipulate them, apply styles, bind events, and perform other operations.

In contrast, getElementById() is a native JavaScript method that selects an element based on its ID. While it is effective, it does not return a jQuery object and lacks the additional capabilities that jQuery provides, such as chaining methods.

querySelector() is another native JavaScript method that allows for selecting elements using CSS selectors. While it offers powerful selection capabilities, similar to jQuery's functionality, it also does not return jQuery objects, which limits its use in the context of jQuery's rich set of methods.

document.element() is not a valid method for selecting elements in either jQuery or vanilla JavaScript, making it an incorrect option in this context.

Thus, using $() for element selection in jQuery stands out as the most effective method, aligning well with the library's design and convenience for developers.