Which three of these Metro Ethernet services map to E-Line services that are defined by the MEF？ （）

A. NAC can authenticate using 802.1X and IBNS cannot
B. NAC can ensure only compliant machines connect and IBNS cannot
C. NAC can ensure access to the correct network resources and IBNS cannot
D. NAC can manage user mobility and reduce overhead costs and IBNS cannot

A. Layer 2
B. Layer 3
C. in-band
D. out-of-band
E. edge
F. central