The ampersand (&) and less-than (<) characters have special meaning in XML and cannot appear directly in text content. A standard parser will report a well-formedness error. They must be escaped using the predefined entities & and < respectively, or the text can be placed within a CDATA section.

In a DTD, enumerated attribute types are defined using parentheses and the pipe (|) separator to list the possible token values. Option A correctly defines an attribute named ‘status’ for an ‘element’ that must have one of the three specified values.

Mixed content is specifically designed for elements that contain both text (#PCDATA) and child elements interleaved. This is the correct model for prose that includes embedded markup for formatting, as described in the scenario.

The ‘book’ element is the parent (and likely the root) containing three child elements: ‘title’, ‘author’, and ‘chapter’. The ‘author’ element correctly has an attribute named ‘role’ with the value “primary” and also contains the text “Jane Doe”.

This is a key differentiator. XML Schema provides a powerful set of built-in and user-definable data types (e.g., xsd:decimal, xsd:date) and is designed to work seamlessly with XML Namespaces. DTDs lack strong data typing (everything is essentially text or tokens) and have problematic, non-standard support for namespaces.

The encoding declaration in the XML prolog specifies the character encoding (e.g., UTF-8, UTF-16, ISO-8859-1) of the document’s physical storage. The parser uses this information to correctly translate the file’s bytes into the Unicode characters that make up the logical XML content.

Setting the ‘abstract’ attribute to “true” on a complex type definition means that this type cannot be used directly in an instance document. It can only be used as a base type for derivation (via extension or restriction), and a derived, non-abstract type must be used in the instance.

XML elements are semantically neutral; they carry no default presentation semantics (unlike HTML’s

,

, etc.). CSS can change visual properties like color and font, but it cannot impart semantic meaning or alter the document’s logical structure, which is a key difference from its use with HTML.

Option A is well-formed: it has a properly opened and closed element with an attribute value enclosed in double quotes. Option B is not well-formed (attribute value lacks quotes). Option C has a mismatched case in the closing tag (‘Note’ vs ‘note’). Option D, while possibly valid for a different design, is not well-formed in the context of the base specification because it mixes an element and text as direct children without a mixed content model declared (though a parser might accept it, it’s not strictly well-formed without a proper model).

The ampersand (&) and less-than (<) characters have special meaning in XML and cannot appear directly in text content. A standard parser will report a well-formedness error. They must be escaped using the predefined entities & and < respectively, or the text can be placed within a CDATA section.0