Exchange 2013 Core Solutions Exam Question

I had the following question on the 70-341 Exam and was curious to what the answer might be.

You install a Mailbox Server role and Client Access role on a new server ex1.contoso.com

You open all the ports required to access its services from the internet, and connect successfully.

You need to identify which types of Exchange Server clients will connect WITHOUT any further configuration.

A Internal OWA  (works)
B Android using ActiveSync (also works)
C Windows Phone 7 using ActiveSync (worked fine too)
D Windows RT Mail App. ( not idea)

Now I think the answer is A, Internal OWA.

However I did set the External URIs for Activesync and B and C work too.

I didn't have to run a command-let to turn it "ON" or anything else, to me that
means it works out of the box.

I had to do was accept the security alerts on the android phone.

Its such a poor question, as it did not specific (further configuration of what exactly.
I assume it refers to Exchange and not the phone.

Any Idea's

Cheers.