A Chief Finance Officer receives an email from someone who is possibly impersonating the company's Chief Executive Officer and requesting a financial operation. Which of the following should an…

PKI (Public Key Infrastructure) is used for digital certificates and secure communication, but its direct application to verify an email's sender in the context of CEO impersonation is less direct than DKIM.

MFA (Multi-Factor Authentication) adds layers of security to user logins but does not directly verify the authenticity of an email's sender or content.

SMTP (Simple Mail Transfer Protocol) is the protocol for sending emails, but it inherently lacks strong authentication mechanisms to prevent spoofing without additional protocols like DKIM or SPF.

DomainKeys Identified Mail (DKIM) is an email authentication method that uses a digital signature linked to a domain name to verify the sender and ensure the email content has not been tampered with in transit. An analyst can inspect the DKIM signature in the email headers to determine if the email truly originated from the CEO's domain or if it is a spoofed message, thus confirming an impersonation attempt.