Consider the snippet given below.
<X style="background-color:black;color:white;padding:20px;"> <h2>London</h2> <p>London is the capital city of England. It is the most populous city in the United Kingdom.</p> </X>
Here, X is used as a container for other HTML elements and has no required attributes. However, style, class and id are common. What could X be in this context?