The correct answer is RTPImportant PointsUser Datagram Protocol (UDP): UDP is an unreliable connectionless-transport layer Protocol used for its simplicity and efficiency in applications where error can be provided by the application layer.Transmission Control Protocol (TCP): TCP is a reliable connection-oriented protocol that can be used in any application where reliability is important.File Transfer Protocol (FTP): FTP is a standard protocol provided by TCP/IP protocol for copying a file from one host to another.Real-time Transport Protocol (RTP): RTP is a network protocol for delivering audio and video over IP networks. It is designed to handle real-time traffic on the internet.Additional InformationRTP is the first time published in 1996 and known as RFC 1889. And next, it published in 2003 with the name of RFC 3550.Applications of RTP :RTP mainly helps in media mixing, sequencing, and time-stamping.Voice over Internet Protocol (VoIP)Video Teleconferencing over the Internet.Internet Audio and video streaming.RTP combines its data transport with a control protocol (RTCP), which makes it possible to monitor data delivery for large multicast networks. Monitoring allows the receiver to detect if there is any packet loss and to compensate for any delay jitter. Both protocols work independently of the underlying Transport layer and Network layer protocols. Information in the RTP header tells the receiver how to reconstruct the data and describes how the codec bitstreams are packetized. As a rule, RTP runs on top of the User Datagram Protocol (UDP), although it can use other transport protocols. Both the Session Initiation Protocol (SIP) and H.323 use RTP.