Which IOS features are used to avoid Routing loops when dynamic Routing protocols are used between PE and CE in MPLS-VPN networks?

A.
Site Of Origin SOO.

B.
SHAM links with OSPF

C.
BGP cost community

D.
BGP feature allow-as in

E.
RPF Reverse Path forwarding.

F.
Access-list Control in Distance Vector protocol like RIP and EIGRP.