Which of the following most likely describes why a security engineer would configure all outbound emails to use S/MIME digital signatures?

Configuring all outbound emails with S/MIME digital signatures primarily ensures non-repudiation. Non-repudiation guarantees that the sender cannot later deny having sent the email, as the digital signature cryptographically links the message to their private key. This provides strong evidence of origin and integrity. While S/MIME can contribute to meeting compliance standards that require message integrity and sender authenticity, non-repudiation is the direct security principle it enforces. It does not inherently increase delivery rates, nor is its primary function to block phishing attacks, though it can help recipients verify legitimate senders.