According to the XMPP Core specification, RFC 6120, a stanza is a "push" mechanism for sending information. The most common and fundamental child elements for conveying the content of a textual message are and . The element contains the primary, human-readable content of the message, while the element provides a topic or title for the conversation, similar to an email subject line. These two elements are central to defining the payload of a standard XMPP message.

A. This is not a standard child element of a stanza as defined by the core XMPP specifications.
B. While a valid child, it reports processing errors and is not part of the message's primary content. and define the actual payload.
C. This is not a standard child element of a stanza. The terms "client" and "server" describe entity roles, not stanza elements.

1. Internet Engineering Task Force (IETF) RFC 6120: Extensible Messaging and Presence Protocol (XMPP): Core.

Section 8.2.3

"Message Stanza

" Paragraph 1: "Common child elements of stanzas include but are not limited to and for capturing the subject and body of a textual message..." This directly supports the inclusion of and .

Section 8.3

"Stanza Errors

" Paragraph 1: This section explains that an element can be a child of a stanza

but its purpose is to report an error

distinguishing it from primary content elements.

2. Cisco

"Developer Guide for the IM and Presence Service

Release 14

" Page 11.

Chapter: "XMPP API

" Section: "Message Stanza": "The message stanza can contain several child elements

such as

and . The element contains the content of the message." This Cisco documentation confirms that and are expected child elements.