Which statement is true about IAM identity domains in Oracle Cloud Infrastructure (OCI)?

They enable customers to merge multiple (XI tenancies into a single identity domain, which can then be managed as a single unit.

They enable customers to create a new OCT tenancy by importing user, group, and access policies from an existing tenancy.

They enable customers to share user, group, and access policies between multiple OCI tenancies.

They enable customers to partition an OCI tenancy into multiple identity domains, each with its own set of users, groups, and access policies.