Explanation : HTML and XML are like brother and sister. Their mother is SGML. SGML (Standard Generalized Markup Language) is the overriding language that produced both XML and HTML. SGML is not a language, but rather a series of commands that are all understood by another program. A similar example would be JavaScript. By itself, there's not much to it, but if you use the JavaScript commands in a particular order and then allow a Web browser to read it, you get some neat effects. So correct option is (A)