Company XYZ has 30 sites using MPLS L3 VPN and is concerned about data integrity.

D (Group Encrypted Transport VPN - GET VPN):GET VPN encrypts traffic across private WANs like MPLS while maintaining full-mesh routing visibility and offering centralized key management with minimal encapsulation overhead.

Other options explained:

A: S-VTI is used for point-to-point IPsec tunnels.

B: DMVPN is used for dynamic multipoint Internet-based VPNs.

C: MGRE is a tunneling protocol but lacks security features.