An attacker posing as the Chief Executive Officer calls an employee and instructs the employee to buy gift cards. Which of the following techniques is the attacker using?

The correct answer is Impersonating. The attacker is pretending to be someone else (the CEO) to trick the employee. This is a classic social engineering tactic where the attacker assumes a false identity to gain trust or access. Smishing is incorrect because it refers to phishing attacks conducted via SMS text messages. While the attacker is using social engineering, the primary method described is a phone call, not a text. Disinformation is incorrect because it involves spreading false information, which isn't the core technique described here; the core is the false identity. Whaling is incorrect because, while it involves targeting high-profile individuals like a CEO, the scenario describes the attacker posing as the CEO to target an employee, not targeting the CEO directly.