Which of the following best describes the purpose of email authentication?

The primary purpose of email authentication is to verify the sender's identity and reduce fraud. This process involves implementing various protocols and techniques to ensure that the email messages are indeed sent by legitimate sources. By doing so, it helps prevent malicious activities such as phishing, spoofing, and spam, which can compromise both personal and professional communications.

Email authentication methods like SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance) play critical roles in establishing the authenticity of emails. They function by validating the sender's domain, checking for proper digital signatures, and ensuring that the email complies with specified policies. This not only enhances the security of email communications but also builds trust among users regarding the emails they receive.

In contrast, the other choices focus on aspects not directly related to authentication. Increasing email capacity limits pertains to storage capabilities rather than verifying identity. Organizing emails into priority sections deals with management and user experience rather than security measures. Enhancing email formatting standards relates to how emails look and are presented, which does not contribute directly to verifying their legitimacy or reducing fraudulent activities.