Right answer is (a) <applet>
Easiest explanation: <applet> is known as HTML Applet Element. It embeds Java applet into the document. But now a days use of Java applets on Web is deprecated. Most of the browsers no longer support use of plug-ins. <embed> element embeds external content in document. <noembed> is fallback content for browsers. <object> element describes an external resource.
