You want to prevent users from accidentally deleting a Shared VPC host project. Which organization- level policy constraint should you enable?

To prevent accidental deletion of a critical project like a Shared VPC host project, you should first place a lien on the project. A lien prevents the project's deletion. However, users with the resourcemanager.projectLiens.update permission can remove liens. The organization policy constraint compute.restrictXpnProjectLienRemoval prevents even those users from removing liens on Shared VPC host projects, providing the strongest protection against accidental deletion. This ensures the project and its network resources remain intact.

A. compute.restrictSharedVpcHostProjects restricts which projects can be designated as host projects; it does not prevent their deletion once configured.
C. compute.restrictSharedVpcSubnetworks controls which subnetworks can be shared with service projects, which is unrelated to host project deletion.
D. compute.sharedReservationsOwnerProjects is a constraint related to Compute Engine reservations and has no effect on project deletion.

1. Google Cloud Documentation, "Protecting projects". This page describes using project liens to prevent accidental deletion. Section: "Using project liens to prevent project deletion".

2. Google Cloud Documentation, "Organization policy constraints for Shared VPC". This document explicitly states that compute.restrictXpnProjectLienRemoval, when set to true, "Prevents users from removing liens on Shared VPC host projects."

3. Google Cloud Documentation, "Provisioning Shared VPC". The "Protect the host project" section recommends adding a project lien and using the compute.restrictXpnProjectLienRemoval organization policy for protection.