Which IOS features are used to avoid Routing loops when dynamic Routing protocols are used betweenPE 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.