What explains this configuration?

The VPN named my_vpn is operating on interface s0/0 of a PE-router. The CE-PE routing protocol
is RIP. The MPLS backbone IGP is OSPF. However, when you review the configuration for the
PE-router, you find that BGP has been configured.
What explains this configuration?

A.
VPN routes are always imported and exported using MP-BGP.

B.
This router is configured improperly.
BGP is not needed in this configuration.

C.
This router is configured improperly.
E-BGP is the required routing protocol between PE and CE-routers.

D.
BGP should be configured on all routers supporting MPLS to ensure backward-compatibility
reasons for earlier version of IOS.

Explanation:
BGP distributes reachability information for VPN-IPv4 prefixes for each VPN. BGP communication
takes place at two levels: within IP domains, known as an autonomous systems (interior BGP or
IBGP) and between autonomous systems (external BGP or EBGP). PE-PE or PE-RR (route
reflector) sessions are IBGP sessions, and PE-CE sessions are EBGP sessions

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