You are proposing HPE Aruba Networking ZTNA to an organization that currently uses a third-party,...

HPE Aruba Networking ZTNA (delivered as part of Aruba SSE) replaces traditional network-level VPN access with application-level access. Key security advantages highlighted in Aruba ZTNA/SSE collateral include:

Applications are no longer exposed directly to the internet; instead, they are fronted by the ZTNA service.

Inbound connectivity to private apps is outbound-only via connectors, eliminating open listening ports and shrinking the external attack surface. www6.h3c.com

Users are granted access only to specific applications, not entire subnets, thereby limiting lateral movement and the blast radius of a compromise.

Aruba documentation explicitly notes that ZTNA “reduces the overall attack surface” and avoids the broad network exposure inherent in classic client-to-site VPNs.

Thus, the most accurate advantage is: ZTNA shrinks the attack surface, eliminating publicly exposed ports and reducing the extent of the private network exposed to remote users → Option D.