NA

Correct Option: B

The xmlns attribute specifies the xml namespace for a document. It is manadatory in XHTML while in HTML5 it is optional. The root element of an XHTML document must be html, and must contain an xmlns atrribute to associate it with the XHTML namespace.

NA

Correct Option: C

Basically parsers are used in softwares and they convert user data into machine data in short in memory form to use. In XML, parser is used to read XML. If an XML document lacks encoding specification, an XML parser assumes that the encoding is UTF-8 or UTF-16.

NA

Correct Option: C

XHTML+RDFa (Extensible Hypertext Markup Language + Resource Description Framework in attributes) is an extended version of the XHTML markup language for supporting RDF through a collection of attributes and processing rules in the form of well-formed XML documents.

NA

Correct Option: B

XML is markup language while XHTML is extensible hypertext version of markup language. XHTML is HTML defined as an XML application. XHTML is stricter than HTML.

NA

Correct Option: D

There are seven layers namely Physical layer, data Link layer, network Layer, transport layer, session layer, presentation layer, and application layer. The physical layer is the first layer, it is used for transmitting electrical signal across the network. Examples are USB, Bluetooth or Ethernet.