You are setting up a Site-to-Site VPN connection between your on-premises network and OCI.

Objective: Identify essential info for CPE to establish a Site-to-Site VPN with OCI.

Option A: Region and availability domain are for OCI resource placement, not CPE config—incorrect.

Option B: The DRG’s public IP is the VPN endpoint, and the IKE pre-shared key authenticates the tunnel—essential and correct.

Option C: OCID and compartment ID are for OCI management, not CPE setup—incorrect.

Option D: Subnet CIDRs are for routing, configured later, not for tunnel establishment—incorrect.

Conclusion: Option B provides the critical VPN connection details.

Oracle documentation states:

"To configure your CPE for Site-to-Site VPN, you need the public IP address of the DRG (VPN headend) and the IKE pre-shared key from the OCI console."This confirms Option B. Reference:Setting Up IPSec VPN - Oracle Help Center(docs.oracle.com/en-us/iaas/Content/Network/Tasks/settingupIPSec.htm).