Directing a top level domain to a subsite of a multisite.


The domain is the main site of a multisite.
A subsite named businessangel has been created.

I need the domain -> to point to the subsite businessangel and keep its name in place as a part of the subsite. How do I proceed to get this working?

EDIT: I notice the plugins Domain Mapping and Multi-Domains. Which plugin should I use for the above?

Thank you.