Answer:
A. Command and control (C&C) server.
Step-by-step explanation:
The name of the threat actor's computer that gives instructions to an infected computer is "Command and control (C&C) server."
The Command and control (C&C) server is usually controlled by an attacker. It is sends commands to systems which have been exposed to malware. It can also receive data which had been stolen from the network it targets.