Your network contains an Active Directory domainnamed contoso.com.
The network has a branch office site that contains a read-only domain controller (RODC) named RODC1.
RODC1runs Windows Server 2008 R2.
A usernamed User1 logs on to a computer in the branch office site.
You discover that the password of User1 is not stored on RODC1.
You need to ensure that User1’s password is stored on RODC1.
What should you modify?

A.
the Member Of properties of RODC1

B.
the Member Of properties of User1

C.
the Security properties of RODC1

D.
the Security properties of User1

Explanation:
http://technet.microsoft.com/en-us/library/rodc-guidance-for-administering-the-password-replication-policy%
28v=ws.10%29.aspx
Administering the Password Replication Policy
Personal comment:
Basically, these are the default settings for the Password Replication Policy of a specific RODC:

So, if you would add a user to be a member of a group that is allowed to store passwords on that specific
RODC, then that user’s password would be stored on that RODC.