Harry, a professional hacker, targets the IT infrastructure of an organization. After preparing for the attack, he attempts to enter the target networkusing techniques such as sending spear$-$phishing emails and exploiting vulnerabilities on publicly available servers. Using these techniques, hesuccessfully deployed malware on the target system to establish an outbound connection.What is the APT lifecycle phase that Harry is currently executing?A$.$ Initial intrusionB. PersistenceC. CleanupD. Preparation