You manage an Active Directory Domain Services forest that contains a root domain named contoso.com and a child domain named branch.contoso.com. You
have three servers named SRV01, SRV02, and SRV03. All servers run Windows Server 2012 R2. SRV01 and SRV02 are domain controllers for the domain
contoso.com. SRV03 is the domain controller for branch.contoso.com. User accounts and resources exist in both domains. All resources in branch.contoso.com are
physically located in a remote branch office.
The remote branch office must be configured as Read-Only Domain Controller (RODC). The solution must minimize the impact on users and the number of servers
deployed in the branch office.
You need to configure the environment.
Which three actions should you perform in sequence? To answer, move the appropriate actions from the list of actions to the answer area and arrange them in the
correct order.
Select and Place:
Answer: 
1. ADMT
2. Uninstall
3. Install
It seems that ADMT should be the first step, because it supports SID history migration.
Otherwise, users would lose access to the objects they owned, as exposed in https://blog.thesysadmins.co.uk/admt-series-3-sid-history.html
“When you migrate an object to another domain, the object is assigned a new SID. Because you assign permissions to objects based on SIDs, when the SID changes, the user loses access to that resource until you can reassign permissions.”
Envikx is right. Because branch.contoso.com is deleted are SID unimportant. ADMT is the migration tool for active directory! Why use ldifde.exe?
So Envikx is correct in saying
1. ADMT
2. Uninstall AD DS from SRV03
3. Install an RODC on SRV03
?
Nope. It’s
1. ADMT
2. Uninstall
3. Install
SID is gone using ldifde.exe. The scenario states “The solution must minimize the impact on users and the number of servers”
ldifde.exe has been around for years. ADMT is newer. Microsoft would not ask questions concerning old tech.