Which of the following is NOT a form of email authentication?

The correct answer is CPC.SPF(Sender Policy Framework),DKIM(Domain Keys Identified Mail),BIMI(Brand Indicators for Message Identification),andDMARC(Domain-based Message Authentication,Reporting,and Conformance)areall forms of email authentication aimed at verifying the authenticity of emails and ensuring they are not spoofed or tampered with.SPF allows domain owners to specify which IP addresses are allowed to send emails on behalf of their domain,D KIM adds a digital signature to emails to verify their authenticity,BIM I enhances brand visibility in email in boxes,and D MARC provides instructions on how email providers should handle messages that failS PF and D KIM checks.On the other hand,CPC is not a recognized form of email authentication.It's essential to implement robust email authentication protocols likeS PF,DKIM,BIMI,andDMARCto enhance email deliver ability,protect sender reputation,and combat phishing and spoofing attacks.