With respect to a TCP connection between a client and a server, which one of the following statements is true?

The correct option is: The client and server can initiate closing of the connection at the same time

To understand why this statement is true, let us analyze each of the options in detail:

1. Simultaneous Connection Termination (The Correct Option):
In TCP (Transmission Control Protocol), connection release is symmetric. Either of the two endpoints (the client or the server) can initiate the connection teardown by sending a FIN packet. Because both peers operate independently, it is entirely possible for both the client and the server to decide to close the connection simultaneously. When this happens, both send a FIN packet at the same time, and each side transitions through the CLOSING state after receiving the other's FIN, eventually terminating the connection safely. Therefore, the statement "The client and server can initiate closing of the connection at the same time" is true.

2. Connection Establishment (Handshake):
TCP uses a three-way handshake (SYN, SYN-ACK, ACK) to establish a connection, not a two-way handshake. A two-way handshake is insufficient because it does not guarantee mutual synchronization of sequence numbers in both directions under network delays. Thus, the first option is false.

3. Initiating Connection Close:
TCP does not restrict connection teardown initiation to the client. The server is fully capable of initiating the close sequence first (active close) by sending a FIN segment before the client does. Thus, the second option is false.

4. Duplex Mode:
A TCP connection is full-duplex. This means data can be transmitted in both directions simultaneously over the same connection. It is not half-duplex. Thus, the third option is false.