Which statements are true of object classes in an LDAP directory?

Which statements are true of object classes in an LDAP directory? (Choose two.)

A.
An entry can’t have more than one auxiliary object class

B.
Auxiliary object classes – When used on their own – provide access to extended schema

C.
An entry can’t have more than one structural object class

D.
Abstract object classes are no longer officially support by the LDAP protocol

E.
Once an entry has been created, its structural object class can’t be changed without re-creating the entry