Which command is required on the fastethernet 0/0 interface of RouterB to resolve this issue?

Refer to the exhibit.

The DHCP client is unable to receive an IP address from the DHCP server

RouterB is configured as follows:

Which command is required on the fastethernet 0/0 interface of RouterB to resolve this issue?
A . RouterB(config-if)#lp helper-address 172.31.1.1
B . RouterB(config-if)#ip helper-address 255.255.255.255
C . RouterB(config-if)#lp helper-address 172.16.1.1
D . RouterB(config-if)#lp helper-address 172.16.1.2

Answer: D