【单选题】Study the exhibit carefully. Routers A and B are customer routers. Routers 1, 2, 3 and 4 are provider routers. The routers areoperating with various IOS versions. Which frame mode MPLS configuration s...
A.
Before MPLS is enabled, the ip cef command is only requited on routers 1 and 4
B.
After MPLS is enabled, the ip cef command is only required on routers 1 and 4
C.
Before MPLS is enabled, the ip cef command is only required on the Ethernet 0 interfaces ofrouters 1 and 4
D.
After MPLS is enabled, the ip cef command is only required on the Ethernet 0 interfaces ofrouters 1 and 4
E.
Before MPLS is enabled, the ip cef command must be applied to all provider routers