What is the most typical use of an overlapping VPN?

A.
Service providers supporting managed CE Services

B.
Service providers supporting carrier-over-carrier MPLS implementions

C.
Simple intranet VPN implementations

D.
Companies that use MPLS VPNs to implement both intranet and extranet services

Explanation:
There are two typical uses for overlapping VPNs:
3) Companies that use MPLS VPNs to implement both intranet and extranet services might use
overlapping VPNs. In this scenario, each company participating in the extranet VPN would
probably deploy a security mechanism on its customer edge (CE) routers to prevent other
companies participating in the VPN from gaining access to other sites in other customer VPN
4) A security-conscious company might decide to limit visibility between different departments in
the
organization. Overlapping VPNs might be used as a solution in this case

Cisco Press – Implementing Cisco MPLS study guide p.6-20