Which command should you run in each domain?

You deploy an Active Directory forest that contains two domains named contoso.com and child.contoso.com.
You plan to deploy Exchange Server 2013 servers to the child.contoso.com domain.
You need to prepare Active Directory for the installation of the first Exchange Server 2013 servers.
Which command should you run in each domain? (To answer, drag the appropriate commands to the correct domains. Each command may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content.)
Select and Place:

Correct Answer:

Explanation/Reference:
THE SUPPLIED ANSWER IS CORRECT.
FOR 3 STEPS USE
1. SETUP/PREPARESCHEMA
2. SETUP/PREPAREAD
3. SETUP /PREPAREDOMAIN
HOWEVER THE ANSWER ONLY PROVIDES FOR 2 STEPS.
IF YOU RUN SETUP /PREPAREAD THEN THIS COMMAND CHECKS TO SEE IF THE SCHEMA
EXTENSIONS HAVE BEEN INSTALLED
AND IF NOT THEN IT PROCEEDS TO INSTALL THEM.
HENCE SETUP /PREPAREAD IS CORRECT
A TRICK QUESTION FROM MICROSOFT TO CHECK IF YOU KNOW HOW SETUP /PREPAREAD
ACTUALLY OPERATES.
References
http://messagingserversupport.com/2013/03/06/how-to-install-exchange-2013-rtm-on-windows-server-2012/
http://books.google.com.au/books?id=3bIRAAAAQBAJ&pg=PA323&lpg=PA323&dq=prepare+child+domains+for+exchange
+2013&source=bl&ots=9OBBo0R2H9&sig=iu1yUeD2ckRsBryxGHi6MTs8Bk&hl=en&sa=X&ei=YPPUfblDqauiQezrYCoCw& ved=0CG8Q6AEwBw#v=onepage&q=prepare%20child%20domains%20for%20exchange%202013&f=false
Prepare Active Directory and Domains: Exchange 2013 Help