HOTSPOT
You have an Exchange Server 2013 organization that contains three servers. The servers are
configured as shown in the following table.
All of the servers are part of a database availability group (DAG) named DAG1.
The databases are configured as shown in the following table.
All of the databases replicate between all the members of DAG1.
You plan to move all mailboxes from DB1 to DB2.
You need to ensure that the passive copies of DB1 are in a healthy state before you move the
mailboxes.
Which command should you run? (To answer, select the appropriate options in the dialog box in the
answer area.)
Answer: 
Set-MailboxDatabase cmdlet to configure a variety of properties for a mailbox database.
DataMoveReplicationConstraint parameter specifies the throttling behavior for high availability mailbox moves.
AllDatacenters At least one passive mailbox database copy in each Active Directory site must have the most recent changes replicated.
WRONG- Set-MailboxDatabaseCopy cmdlet to configure the properties of a database copy.
set-mailboxdatabase is correct, however -alldatacenters is incorrect as it is not parameter.
Should be set-mailboxdatabase DB1 -DataMoveReplicationConstraint -SecondDatacenter.
https://technet.microsoft.com/en-us/library/bb123971(v=exchg.160).aspx
SecondDatacenter At least one passive mailbox database copy in another Active Directory site must have the most recent changes replicated. Use this setting to indicate that the database is replicated to database copies in multiple Active Directory sites.