A complete HTML table structure uses as the container, for table rows, and for table data cells. Option A incorrectly uses (not a table tag), option B uses (an HTML document element, not a table element), and option D uses (teletype text, not a table tag).

The tag with the src attribute is the correct syntax for inserting images in HTML. Option A uses incorrect closing syntax (images are self-closing), option B uses a non-existent tag, and option C uses href instead of src.

Active Server Pages (ASP) use the .asp file extension to indicate that the web page contains server-side script. The .ascx extension is for ASP.NET user controls, not classic ASP pages. .asd and .asc are not standard ASP extensions.

ColdFusion files use .cfm and .cfml extensions. CFM stands for ColdFusion Markup, and CFML is ColdFusion Markup Language. The other options (cam/caml, cofm/cofml, cofn/cofnl) are not valid ColdFusion file extensions.

ASP.NET Web Handler files use the .ashx extension. ASHX files are used for HTTP handlers that process web requests. ASPX is for regular ASP.NET pages, ASCX is for user controls, and ASMx is a typo.

HTML files use the .html extension (or .htm as a shorter variant). HTA is for HTML Applications, HTX is an older index server extension, and httml is not a valid extension. HTML is the standard markup language for web pages.

ASHX is the file extension for ASP.NET Generic Handlers, which process HTTP requests without the overhead of a full web page. They're used for AJAX calls, file downloads, and lightweight HTTP endpoints.

HTML files use the .html extension (and the shorter .htm variant). These contain markup code that web browsers render as web pages. HTML is the standard language for creating web pages.

HTML elements without content are called Empty elements. They don't have closing tags and can't contain child elements. Examples include
, , ,

The tag defines alternative content that displays when scripts are disabled or not supported. It's essential for graceful degradation - browsers with JavaScript off see the noscript content instead. There is no or tag in HTML.

HTML provides six levels of headings using

through

tags, where h1 represents the main heading and h6 the lowest-level subheading. These are semantic tags that convey document structure.

Every validation control in ASP.NET requires the ControlToValidate property to specify which input control to validate. Additionally, validation controls support the Text property to display validation error messages. Therefore, both properties are found in validation controls.

ASP.NET authorization sections use both and elements to control access rules. These elements specify which users or roles can or cannot access specific resources, forming the complete authorization framework.

The @Page directive is used in ASP.NET to define page-specific attributes like the programming language, master page file, or other configuration settings at the top of an .aspx file. @Register is used for registering user controls and custom tag prefixes, while @control is not a standard ASP.NET directive.

A Document Type Definition (DTD) is a traditional way to describe and validate the structure and legal elements of an XML document. XML Schema (XSD) is another, more modern alternative.