When EIGRP is used as the PE-CE routing protocol which of these statements is correct?（）

A. EIGRP can be used only as the PE-CE routing protocol if the PE and CE routers are in the same AS
B. Other EIGRP AS routes are automatically advertised to the CE router and do not require a redistribution configuration command to be configured
C. Unlike other routing protocols that are used between PE and CE routers, EIGRP supports backdoor links
D. Configure of the VPN is only required on the PE router