A botnet can be managed through which of the following?

IRC was the original and most common command-and-control (C2) channel for botnets because its real-time chat protocol allows a bot herder to join a private channel and broadcast commands to all infected hosts simultaneously. The protocol is lightweight, widely available, and supports pseudonymous operation, making it ideal for covert botnet management. Early botnets like EggDrop and later malware families like SDBot were built explicitly around IRC-based C2 infrastructure.

While email has been used in some botnet designs for C2 communication, it is not the primary or most common mechanism and is far less efficient than IRC for real-time command broadcasting.

Social media platforms like LinkedIn and Facebook are not standard or reliable botnet C2 channels, as they are easily monitored and accounts are subject to takedown.

A vulnerable FTP server is a target for exploitation or a staging area for malware payloads, not a management channel used to issue commands to a botnet.