Which of the following are the ways of sending secure e-mail messages over the Internet? Each correct answer represents a complete solution. Choose two.

S/MIME (Secure/Multipurpose Internet Mail Extensions) uses public-key infrastructure (PKI) certificates to encrypt and digitally sign email content, providing end-to-end security and is natively supported in most enterprise email clients.

TLS secures the transport channel between mail servers (e.g., SMTP over TLS), but it does not provide end-to-end message encryption - the email content is decrypted at each mail server hop, so it is not a complete solution for securing the message itself.

PGP (Pretty Good Privacy) uses a web-of-trust model with public/private key pairs to encrypt and sign email messages end-to-end, and its open standard OpenPGP (RFC 4880) is widely used for secure personal and organizational email communication.

IPSec operates at the network layer (Layer 3) to secure IP traffic between hosts or networks, and while it can protect the network path, it does not provide email-specific end-to-end message encryption or digital signing.