Consider a network that uses Transmission Control Protocol $($TCP$).$ When a client transmits a SYN packet $($a TCP packet with the SYN flag set to true in the packet header$)$ to a server, the response will be a SYN$/$ACK $($SYN and ACK flags set to true$).$ The client then responds to this SYN$/$ACK with an ACK $($ACK flag set to true$).$ What is this process called?

A$.$A three$-$way handshake

B$.$Passive sniffing

C$.$SYN flood

D$.$Active sniffing