Both SSL VPN and IPsec VPN are standard protocols supported by FortiGate devices for secure remote access. SSL VPN typically uses HTTPS (TCP port 443) for encrypted communication, while IPsec uses protocols like IKE and ESP. Both can be configured between an end-user workstation (e.g., via FortiClient) and a FortiGate device, supporting various authentication methods. All options are correct, making D the correct answer. Exact extract: "SSL VPN technology uses the standard SSL/TLS protocol to provide a secure connection to the FortiGate unit. The FortiGate SSL VPN can be configured to use HTTPS..." and "IPsec VPNs use standardized protocols like IKE and ESP to create secure tunnels... FortiClient supports both IPsec and SSL VPN connections to FortiGate devices for remote access."