An XHTML document must have an XHTML <! DOCTYPE> declaration. The <html>, <head>, <title>, and <body> elements must also be present, and the xmlns attribute in <html> must specify the xml namespace for the document.

Which elements are mandatory in an XHTML document Mcq?

There are as: 1) In XHTML, the DOCTYPE is compulsory, 2) Xmlns attribute in <html> in manndatory, 3) The basic building blocks of markup i.e. <html>, <head>, <title>, and <body> are must in one. 4) Last but not least, XHTML is case sensitive where as HTML is case in-sensitive.

Why

XHTML can impose additional requirements and still be XML as long as the additional requirements do not contradict those of XML. This DOCTYPE requirement is completely consistent with XML. There is no contradiction. There must be a DOCTYPE declaration in the document prior to the root element.