The correct answer is (b) TCP.
In both FTP (File Transfer Protocol) and HTTP (Hypertext Transfer Protocol), after the transfer of a page or file is complete, both the client and the server release the TCP connection. TCP (Transmission Control Protocol) is used to establish reliable communication between the client and the server, and once the data transfer is finished, the connection is closed by both parties.
In HTTP, a TCP connection is used to transfer the requested web page or resource. After the transfer, the server and client typically close the connection, unless the connection is kept open (as in HTTP/1.1's persistent connections).
In FTP, a TCP connection is used to transfer files, and once the transfer is done, the FTP server and client release the connection.
Thus, TCP is the protocol responsible for managing the connection during data transfer, and it is released after the transfer is complete.