You have defined VLANs 31 and 32 on an HP E5400 zl Series switch and assigned untagged ports to both VLANs. You have defined IP addresses for both VLAN interfaces. You have configured IP helper to enable clients in VLAN 31 to receive IP addresses from a DHCP server in VLAN 32. Which other feature must be enabled before the clients will receive addresses from the server?
A. DNS
B. DHCP relay
C. IP routing
D. DHCP snooping