If an XML data instance conforms to its DTD, how is the document classified with respect to type validity?

Introduction / Context:
Validation adds assurance that an XML instance adheres to a declared grammar, traditionally a DTD or, more commonly today, an XML Schema. Understanding the terminology helps in designing reliable integrations and document workflows.

Given Data / Assumptions:

• A DTD exists and the instance has been checked against it.
• The instance conforms to element/attribute declarations and content models.
• We are using classic DTD terminology for “type validity.”

Concept / Approach:
A document is called type-valid when it satisfies all constraints specified by its DTD (or, more generally, by an associated schema language). This goes beyond mere well-formedness by enforcing allowable structures and attribute usage.

Step-by-Step Solution:

Verification / Alternative check:
Validation tools report success with no errors, often building a post-validation infoset including defaults declared in the DTD.

Why Other Options Are Wrong:
type-invalid / not-type-valid: Contradict the stated conformance.
HTML document: Validation status does not change the data format from XML to HTML.

Common Pitfalls:
Assuming well-formed equals valid; many systems require both, but they are distinct checks.

Final Answer:
type-valid.