HOTSPOT
Your network contains an Active Directory domain named contoso.com. The domain
contains two member servers named Server1 and Server2. All servers run Windows Server
2012 R2.
Server1 and Server2 have the Hyper-V server role installed. The servers are configured as
shown in the following table.
You add a third server named Server3 to the network. Server3 has Intel processors.
You need to move VM3 and VM6 to Server3. The solution must minimize downtime on the
virtual machines.
Which method should you use to move each virtual machine?
To answer, select the appropriate method for each virtual machine in the answer area.
Answer: 
Explanation:
VM3: export/import is the only option due to different processor manufacturers
VM6: Live migration can be used as both have Intel CPU’s
Live Storage Migration requires same processor manufacturers
Live migration requires same same processor manufacturers
Quick migration has downtime
http://technet.microsoft.com/en-us/library/dd446679(v=ws.10).aspx
http://technet.microsoft.com/en-us/library/hh831656.aspx
http://technet.microsoft.com/en-us/library/jj628158.aspx
For moving VM6: you can perform a Live Migration only if you have a failover cluster with highly-available vm’s.
The question doesn’t say anything about clustering, nor about shared-storage (if we want to use Hyper-V over SMB share: https://technet.microsoft.com/en-us/library/jj134187.aspx#BKMK_Step6 ). It say only that there are Hyper-V servers, so we can assume that they are stand-alone (also member servers in the domain). In that regard, the correct answer will be “storage migration” for VM6.
Something it’s not clear for me: if we have this option for processor compatibility,on Vm settings, the only way we can use it is with exporting/importing vm’s? For live migration, shared-nothing live migration or quick migration it seems that we need processors form the same family and the same manufacturer.
No it doesn’t. In 2012 and above live migrations hosts don’t have to be clustered
https://technet.microsoft.com/en-us/library/jj134199.aspx