Contoso, Ltd. plans to use Office 365 for email services and Lync Online. Contoso has four unique domain names.
You need to migrate domain names to Office 365.

Which two domain names you could migrate? Each correct answer presents part of the solution.

A.
contoso.us

B.
contoso

C.
contoso.local

D.
contoso.co

Explanation:
There is an allmost indentical question, the answer is the same.
Which two domain names you could/could not migrate ?
http://www.briefmenow.org/microsoft/which-two-domain-names-should-you-exclude-from-the-migration/#comment-275359