Charles works as a Web Developer for Cyber Net Inc. The company frequently receives production information from external vendors in the form of XML data. Charles stores these XML data in a disk container of the Web server as .xsd schema files and .xdr schema files. There are specific rules for writing XML codes to define the structure and data types for XML documents. Which of the following criteria should NOT be considered while writing an XML document?

Each correct answer represents a complete solution. Choose all that apply.