You use a contained database named ContosoDb within a domain. You need to create a user who
can log on to the ContosoDb database. You also need to ensure that you can port the database to
different database servers within the domain without additional user account configurations. Which
type of user should you create?

A.
SQL user without login

B.
SQL user with a custom SID

C.
SQL user with login

D.
Domain user

Explanation:
Reference:
http://msdn.microsoft.com/en-us/library/ff929071.aspx