In HTML, which tag is used for inserting a horizontal rule across the page?

The tag used for inserting a horizontal rule across the page in HTML is <hr>. This tag creates a thematic break in the content and is visually represented as a horizontal line. It is commonly utilized to separate sections of content or to create a visual distinction between different topics within a webpage.

The <hr> tag is a self-closing tag, meaning it does not require a closing tag. This makes it simple to use as it only needs to be added to the HTML where you want the horizontal line to appear.

The other options do not represent valid HTML tags for this purpose. For instance, <rule>, <line>, and <break> do not exist in standard HTML specifications, and thus would not generate a horizontal line or any visual effect when the web page is rendered. Understanding the proper usage of the <hr> tag is essential for creating well-structured and visually appealing web content.