HOTSPOT
Your network contains an Active Directory domain named contoso.com. The domain
contains two servers named Server1 and Server2. All servers run Windows Server 2012 R2.
You install the DHCP Server server role on both servers.
On Server1, you have the DHCP scope configured as shown in the exhibit. (Click the Exhibit button.)
You need to configure the scope to be load-balanced across Server1 and Server2.
What Windows PowerShell cmdlet should you run on Server1?
To answer, select the appropriate options in the answer area.
Answer: 
Explanation:
Answer = “Add-Dhcpserverv4Failover -PartnerServer Server2 -ScopeID 10.0.0.0” -Name ScopeRepl
http://technet.microsoft.com/en-us/library/jj590652.aspx
The correct answer is “Add-DHCPServer4FailOverScope-PartnerServer Server2 -ScopeID 10.0.0.0” -Name ScopeRepl. The question is you need to configure scope to be load balanced not Servers.
https://technet.microsoft.com/en-us/library/jj590727.aspx
You first have to create a failover relationship before you’re able to failover a scope.
So the answer seems to be correct as nowhere is written that a failover scope already exists.
Took a while deciding between Add-Dhcpserverv4Failover and Add-Dhcpserverv4Failoverscope. Sounds like Add-Dhcpserverv4Failover will add all of the scopes from server 1 to server 2 whereas Add-Dhcpserverv4Failoverscope will just add the scope/scopes specified.
Therefore I agree with Sakile
Now starting to think this answer is correct, you type add-dhcpserver4failover and can then specify a particular scope with -scopeID
Detailed Description
The Add-DhcpServerv4Failover cmdlet adds a new IPv4 failover relationship to a Dynamic Host Configuration Protocol (DHCP) server service. The first parameter set adds a failover relationship with load balance mode. The second parameter set adds the failover relationship in hot-standby mode.
This cmdlet creates the failover relationship on both of the DHCP server services with the specified parameters. The ScopeId parameter value specified on the source DHCP server service, or local computer running the DHCP server service is identically setup on the partner DHCP server service.
If the SharedSecret parameter is specified, message digest authentication will be automatically turned on for the newly created failover relationship.
By default, user confirmation will be sought if the SharedSecret parameter is specified.
https://technet.microsoft.com/en-us/library/jj590652.aspx
Fro the graphic it is obvious that there is no existing failover relationship. otherwise there would have been a Failover Tab between the Network Access Protection and Advanced Tabs.
https://technet.microsoft.com/nl-nl/library/hh831385.aspx
Therefore, the answer is correct.
Add–DhcpServerv4Failover – Adds a new IPv4 failover relationship on the DHCP server
Add–DhcpServerv4FailoverScope – Adds the specified scopes to an existing failover relationship
The question asked for load balance,but the answers are failover,is it a poorly written question or is it intentional?
You can add a failover relationship with load balance mode or in hot-standby mode. So the question is a little misleading yes.
Basically failover has two modes… load balance OR hot standby.