Which MPLS VPN implementation allows selected sites in one simple VPN to communicate with selected sites of a second VPN?

A.
Central services VPN

B.
Managed CE router services VPN

C.
Overlapping VPN

D.
Managed PE router services VPN

Explanation:

The "selected sites" are usually the central sites of two customers which create a vpn between them for exchanging data.
The description of overlapping vpn: "Overlapping VPNs are used to provide connectivity between segments of two vpns"