Which of the following controls would prevent an employee from emailing unencrypted information to their personal email account over the corporate network?

DLP solutions monitor, detect, and block data in motion across the network based on content policies. A DLP rule can identify unencrypted sensitive content in outbound SMTP traffic destined for external or personal email addresses and prevent the transmission, which directly addresses the described scenario.

A Certificate Revocation List (CRL) tracks revoked digital certificates and has no capability to inspect or block email content.

A Trusted Platform Module (TPM) is a hardware chip used for local key storage and platform integrity checks, not network traffic inspection.

A Hardware Security Module (HSM) manages cryptographic keys and performs encryption operations but does not monitor or block outbound email traffic.