During a routine analysis of network traffic, your team notices a series of irregular low-and-slow data exfiltration attempts to a command-and-control server. These attempts are highly targeted and sophisticated, demonstrating knowledge of the network's architecture and using encryption to avoid detection. Which type of threat actor is most likely involved in this scenario?
Script kiddie
Insider threat acting unintentionally
Hacktivist
Advanced persistent threat actor
Organized crime
Nation-state acting overtly