A legal services company wants to ensure emails to clients maintain integrity in transit. Which of the following would BEST meet this requirement? (Select TWO)

Signing with the organization's public key is cryptographically incorrect - digital signatures are created using the private key so only the key owner can produce them, and verified with the public key; reversing this breaks the authentication model.

Encrypting bulk email with the private key is not standard practice and does not efficiently provide integrity for multiple external recipients who would need the public key to decrypt, conflating encryption with signing.

Implementing a PKI provides the certificate infrastructure to support signing but is not itself an email integrity mechanism - it does not directly ensure messages are signed or hashed.

Signing an email with the organization's private key creates a digital signature that any recipient can verify using the corresponding public key, proving both that the message originated from the organization and that the content has not been modified in transit - directly satisfying the integrity requirement.

Shared secret keys are used in symmetric encryption for confidentiality and are not suitable for providing verifiable integrity to external clients who do not possess the shared secret.

Hashing all outgoing emails produces a fixed-length digest of the message content; if the hash value is transmitted with the message (or embedded in the signature), the recipient can recompute the hash and detect any alteration, providing an additional integrity verification mechanism.