Cisco 200-301 topic 1 question 962

D can't be answer, because  192.168.10.2 address is not given for any interface, it is just configured on router. We don't know on which interface it is given, since we have only one connected interface, which is even access port. But 192.168.20.2 is given for router interface.
This is why I pick C

Ok this going to be long. Correct me if I am wrong please. 1st we have a multilayer switch with interswitch vlan routing going on.
Ip helper should be applied on the routing interface closest to the clients, because the discover messages cant pass layer 3 interface without ip helper. On the switch we have Interface VLAN 10 192.168.10.1. So any device trying to exit the broadcast domain from vlan 10 has to go thru this interface. So that's where we should apply the IP Helper command on. Then we look for the IP Address of the DHCP Server and it looks like the IP Address of the server is Int g0/0 192.168.20.2. So the correct answer should be SW1(config)int vlan 10 , SW1(config-if)ip helper-address 192.168.20.2

vlan 10 , must be D

The question is asking about clients on VLAN 10 so how can C be correct

yeah it's C and if cisco wants us to be more confused they would show same commands in different SVIs )

It is C. You are thinking of the default gateway, we need the DHCP server address which is 192.168.20.2. The exhibit with the long output is meant to throw us off, just look at the topology diagram and it is there. If we only needed 192.168.10.2 for DHCP for VLAN 10, then we would not need an IP helper address.