What is the proper command to associate interface s0/0 with a VRF named my_vpn?

What is the proper command to associate interface s0/0 with a VRF named my_vpn?

A.
Router (config-vrf)# int s0/0

B.
Router (config-if)# vrf my_vpn

C.
Router (config)# if vrf my_vpn int s0/0

D.
Router (config-if)# ip vrf forwarding my_vpn

Explanation:
After you define all relevant VRFs on the PE router, you must tell the PE router which interfaces
belong to
which VRF and, therefore, should populate the VRF with routes from connected sites. More than
on interface can belong to the same VRF. You can do this by using the ip vrf forwarding interfacemode command, which associates the interface with the name VRF. Both main and sub-interfaces

can be defined within a VRF.

MPLS and VPN Architectures (Ciscopress) page 204