Which of the following options is used to provide a common base for data description and validation
in XML documents?

A.
Schematron

B.
Web service

C.
SOAP

D.
XML schema

Explanation:
An XML schema is used to provide a common base for data description and validation in XML
documents. An XML schema is the building block of an XML document containing a formal
description of what comprises a valid XML document. It defines elements, attributes, child elements,
and the number of child elements that may appear in a document. An XML schema is written in a
particular syntax recommended by the W3C.
Answer B is incorrect. A Web service is a unit of application logic that can be accessible via standard
protocols. A Web service is defined by the W3C as a software system designed to support
interoperable machine-to-machine interaction over a network.
Answer C is incorrect. Simple Object Access Protocol (SOAP) is an XML-based protocol. It is used to
exchange structured and type information on the Web. SOAP defines rules for data encoding. It is
highly extensible and modular because it does not contain application or transport semantics.
Answer A is incorrect. Schematron is a type of language for making assertions about the presence or
absence of patterns in an XML document.