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.
User mapped to an asymmetric key

C.
Domain user

D.
login mapped to a virtual account

Explanation:
If the service must interact with network services, access domain resources like file shares or if it uses linked
server connections to other computers running SQL Server, you might use a minimally-privileged domain
account. Many server-to-server activities can be performed only with a domain user account.
https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/configure-windowsservice-accounts-and-permissions