Markup and Web Languages

HTML tags are enclosed in angle brackets, with the tag name inside. The syntax is for opening tags. Option A shows which is correct. Option B is just the text without brackets, C uses <% %> which is JSP/ASP syntax, and D uses quotes which are not tag delimiters.

The <hr> tag in HTML creates a horizontal rule (line) across the page. It's a self-closing tag that doesn't require content. Option A is not a standard HTML tag, C creates a table row, and D `` doesn't exist as a standard HTML element.

HTML files use the .html file extension as the standard. While .htm was used historically on older systems with 8.3 filename limitations, .html is the modern standard. Option B .shtml is for server-parsed HTML, C .webpage isn't a standard extension, and D .doc is for Microsoft Word documents.

The 'style' attribute in HTML is used to apply inline CSS directly to an element. For example:

Red text

The correct CSS property for making text bold is 'font-weight' with value 'bold'. The selector 'p' targets all paragraph elements. Options B and D use non-existent properties ('text-size', 'font-size' for boldness). Option C uses inline style syntax but with an incorrect property.

Valid CSS syntax uses the selector followed by curly braces: selector { property: value }. Option A correctly shows 'body {color: black}' with proper syntax. Options B and D use incorrect brace placement, option C uses colon incorrectly and equals sign instead of braces.

XML stands for Extensible Markup Language, a text-based markup language designed to store and transport data in a structured, hierarchical format that is both human-readable and machine-readable.

XML enforces well-formedness rules where elements must nest properly without overlapping - an end tag must match the most recent start tag. Attributes must be quoted and have unique names within an element.

XML declaration is a processing instruction that starts with and ends with ?>, making option C the correct syntax. This optional declaration specifies XML version and encoding at the document start.

XML allows two equivalent syntaxes for empty elements: a full open/close tag pair with no content, or a self-closing shorthand. Both are valid and interchangeable.

XML comments are delimited by , allowing documentation within XML documents that parsers ignore. Option A shows the correct syntax though the example appears to have a minor formatting issue.

XML (eXtensible Markup Language) is a recommendation specified by the World Wide Web Consortium (W3C), the main international standards organization for the World Wide Web. The W3C XML specification was first published in 1998 and has gone through multiple versions (1.0, 1.1). W3C is responsible for maintaining and standardizing web technologies including HTML, CSS, and XML to ensure interoperability across different platforms and systems.