Which of the followings are physical compnants for Active Directory

In Active Directory, physical components describe actual hardware/network topology — a Site represents a physical network location, and a Domain Controller is an actual server machine. Organizational Units (OUs) and the Global Catalog (GC) are logical constructs: an OU is a logical container for organizing objects, and the GC is a logical/functional role a domain controller can hold, not a physical thing itself.

• Thanks
• Wrong explanation