To answer this question, you need to understand the requirements for valid XHTML documents. Let's go through each option to understand why it is correct or incorrect:
Option A) All tags must be closed, even stand-alone tags on a single line - This option is correct because in XHTML, all tags must be closed, even stand-alone tags on a single line. This ensures that the document follows the XML syntax.
Option B) All image tags must include a name attribute - This option is incorrect because in XHTML, the name attribute is not required for image tags. The required attributes for image tags are typically src (to specify the image URL) and alt (to provide alternative text for the image).
Option C) All element and attribute names must be lowercase - This option is correct because in XHTML, all element and attribute names must be written in lowercase. XHTML is case-sensitive, and using uppercase letters for element and attribute names would result in invalid markup.
Option D) The document must specify a valid XHTML DOCTYPE - This option is correct because a valid XHTML document must specify a valid DOCTYPE declaration at the beginning. The DOCTYPE declaration specifies the version of XHTML being used and provides the document with a standardized set of rules.
The correct answer is Option B. This option is correct because including a name attribute is not required for image tags in valid XHTML documents.