The correct answer is:
All of the above.
Step-by-step explanation:
The application layer is the topmost layer in the TCP/IP protocol stack. It is responsible for providing services and support to the end-user applications. The application layer programs are designed to run on top of TCP (Transmission Control Protocol) to enable communication between different systems over a network.
1. TELNET:
TELNET is an application layer program that allows remote login to a computer or a server. It enables users to access and control remote systems as if they were directly connected to them. TELNET uses TCP as its transport protocol to establish a reliable connection between the local and remote systems.
2. File Transfer Protocol (FTP):
FTP is an application layer program used for transferring files between a client and a server over a network. It provides a way to upload, download, and manage files on remote servers. FTP uses TCP for reliable data transfer, ensuring that files are transferred correctly.
3. Simple Mail Transfer Protocol (SMTP):
SMTP is an application layer protocol used for sending and receiving emails. It is responsible for the transmission of email messages between mail servers. SMTP uses TCP to establish a connection with the recipient's mail server and deliver the email.
All of the above options - TELNET, FTP, and SMTP - are application layer programs designed to run on top of TCP to provide specific network services. They rely on the underlying TCP protocol for reliable data transfer and communication.
In conclusion, all the options mentioned - TELNET, FTP, and SMTP - are application layer programs that run on top of TCP.