Everything that 'Active Directory' tracks is considered an

In Active Directory, everything that is tracked is considered an object. Option A is correct. Objects are the fundamental entities in AD - users, computers, groups, printers, organizational units, etc. Each object has attributes and is uniquely identifiable. Trees, domains, and forests are logical containers or structures that organize objects, but they themselves are not what AD 'tracks' in the fundamental sense - they group the objects. AD's database stores objects; the hierarchical structures (trees, domains, forests) are ways to organize and manage these objects for administrative purposes.