Which protocol guarantees delivery of data through a connection-based approach?

The Transmission Control Protocol (TCP) is the correct choice as it is a connection-oriented protocol that ensures reliable delivery of data across a network. TCP establishes a connection between the sending and receiving devices before data transfer begins. This connection-oriented approach involves a handshake process, where both parties agree on the communication parameters.

Once the connection is established, TCP guarantees that packets of data are delivered in the correct order and without errors. It accomplishes this through sequence numbers and acknowledgments; if any packets are lost or corrupted during transmission, TCP identifies this and retransmits the necessary packets to ensure complete and accurate delivery.

In contrast, the User Datagram Protocol (UDP) is a connectionless protocol that does not guarantee delivery, making it faster but less reliable for applications that require a robust data transmission. The Internet Control Message Protocol (ICMP) serves primarily for diagnostics and error messaging, rather than for delivering data. Lastly, the File Transfer Protocol (FTP) uses TCP as its transport layer protocol but is specifically designed for file transfer, rather than being a standalone protocol focused on data delivery guarantees. Thus, TCP distinctly stands out for its comprehensive approach to ensuring data delivery reliability.