TCP (Transmission Control Protocol) is a connection-oriented protocol with several key characteristics:

Connectionless : This is not a characteristic of TCP. TCP establishes a connection before transmitting data using a three-way handshake.

Flow control and window mechanism : TCP uses flow control and sliding window mechanisms to manage data transmission rates and prevent buffer overflow.

Connection-oriented : TCP establishes, maintains, and terminates connections between endpoints.

Reliable transmission : TCP ensures reliable delivery of data through acknowledgments, retransmissions, and error detection.

UDP, not TCP, is a connectionless protocol. Therefore, the correct answer is A .