After analyzing and correlating activity from multiple sensors, the security analyst has determined a group from a high-risk country is responsible for a sophisticated breach of the company network and continuous administration of targeted attacks for the past three months. Until now, the attacks went unnoticed. This is an example of:
A.
privilege escalation.
B.
advanced persistent threat.
C.
malicious insider threat.
D.
spear phishing.
Explanation: