All Vault instances, or clusters, include two built-in policies that are created automatically.

Comprehensive and Detailed In-Depth Explanation:

Vault automatically creates two built-in policies: root and default.

A : The root policy is created at initialization, granting superuser privileges (full access to all paths and operations). It’s attached to root tokens and cannot be deleted or modified, per the policies documentation.

C : The default policy is also created automatically, providing basic permissions (e.g., token management). It’s attached to all non-root tokens by default, can be modified, but cannot be deleted, as stated in the docs.

B : No admin policy is automatically created; administrative policies must be defined manually.

D : The default policy can be modified, contradicting this option.