Which configuration should you use?

Your network contains an Active Directory domain named contoso.com. The domain contains a main office and
a branch office. An Active Directory site exists for each office. The domain contains two servers named Server1
and Server2 that run Windows Server 2012 R2.
Both servers have the DHCP Server server role installed. Server1 is located in the main office site.
Server2 is located in the branch office site. Server1 provides IPv4 addresses to the client computers in the
main office site. Server2 provides IPv4 addresses to the client computers in the branch office site.
You need to ensure that if either Server1 or Server2 are offline, the client computers can still obtain IPv4
addresses. The solution must meet the following requirements:
The storage location of the DHCP databases must not be a single point of failure.
Server1 must provide IPv4 addresses to the client computers in the branch office site only if Server2 is
offline.
Server2 must provide IPv4addresses to the client computers in the main office site only if Server1 is offline.
Which configuration should you use?

A.
Load sharing mode failover partners

B.
Hot standby mode failover partners

C.
A Network Load Balancing (NLB) cluster

D.
A failover cluster

Explanation:
http://blogs.technet.com/b/teamdhcp/archive/2012/06/28/ensuring-high-availability-of-dhcpusingwindowsserver-
2012-dhcp-failover.aspx Ensuring
High Availability of DHCP using Windows Server 2012 R2 DHCP Failover The Hot Standby mode results in an
Active-Passive configuration. You will be required to designate one of the two DHCP servers as the active
server and the other as standby. The standby server is dormant with regard to serving client requests as long
as the active server is up.
However, the standby server receives all the inbound lease updates from the active DHCP server and keeps its
database up to date.http://blogs.technet.com/b/teamdhcp/archive/2012/09/03/dhcp-failover-hotstandbymode.aspxDHCP Failover Hot-Standby Mode In the previous blog on DHCP Failover, we discussed the
DHCP failover load balance mode where both DHCP servers respond to client requests and load balance the
requests between them based on an admin specified load distribution ratio. In the other mode of a failover
relationship, known as the Hot-Standby mode (ActivePassive), only one of the servers actively leases IP
addresses and option configuration to clients in given subnet(s)/scope(s) while the other server (standby) is
passive.
The standby server services the clients, only in event of active server being down. The clients fallback to the
active server once the active server becomes available again post the outage. The Load balance mode is more
suited for single site deployment where the 2 DHCP servers in a failover relationship are co-located with the
subnets/scopes being served by them. As the servers are in network proximity with the clients, the clients do
not experience any latency while acquiring or renewing an IP address. Hot-Standby mode is more suited for
multisite deployment topologies. Each site would have a local DHCP server which is configured to provide the
DHCP service to the clients on the local network and DHCP server at a remote site would be standby server. In
a normal state of operation, computers and devices on a given site receive IP addresses and other network
configuration from the DHCP server located at the same site as the clients. However, in the event of the local
DHCP server being down, the DHCP server from the remote site would provide the service to the clients. You
could choose to deploy hot standby mode in a single-site deployment also if you need to.