You need to move all of the virtual machines from Server1 to Server2

Your network contains a server named Server1 that runs Windows Server 2012 R2. Server1 has
the Hyper-V server role installed. Server1 hosts 10 virtual machines that run Windows Server
2012 R2.
You add a new server named Server2. Server2 has faster hard disk drives, more RAM, and a
different processor manufacturer than Server1.
You need to move all of the virtual machines from Server1 to Server2.

The solution must minimize downtime.
What should you do for each virtual machine?

A.
Perform a quick migration.

B.
Perform a storage migration.

C.
Export the virtual machines from Server1 and import the virtual machines to Server2.

D.
Perform a live migration.

Explanation:
C)
Other options require same CPU family and cluster
http://technet.microsoft.com/en-us/library/hh848491.aspx
http://technet.microsoft.com/en-us/library/hh848495.aspx
http://technet.microsoft.com/en-us/library/jj628158.aspx
The different processor manufacturer is the key here.
Storage, Live, and Quick all require same manufacturer.