What is the correct way to add a default-styled button to an <a> tag?

The correct approach to add a default-styled button to an <a> tag is by using a combination of the appropriate attributes and classes. The option that states <a href="#" class="btn btn-default">Button</a> accurately represents this.

In this example, the <a> tag is utilized as a link, which allows it to have the navigational behavior typical of hyperlinks, while the classes "btn" and "btn-default" are included to apply the necessary styles that resemble a button. It leverages CSS classes that are often defined in frameworks like Bootstrap, which use these class names to style the link to look like a traditional button.

This method provides both the functional and stylistic inclusion of a button within an anchor tag, allowing users to interact with it as they would with any other button while maintaining its link characteristics.