The router SIS-R has been configured in a CIS network. As a network administrator, you were required to enable MPLS on that router. Which of the following description is making sense on the basis of the output information?（）

• A、CEF switching is only needed to forward labeled packets.
• B、CEF switching is needed on both ingress and egress interfaces on which MPLS is enabled.
• C、Interface-level CEF switching is needed only on egress interfaces that are sending IP packets on which the egress LSR performs the label imposition process.
• D、Interface-level CEF switching is needed only on ingress interfaces that are receiving IP packets on which the ingress LSR performs the label imposition process.