When upgrading a Samba 3 to a Samba 4 Active Directory domain using samba-tool domain classicupgrade, which of the following statements are true? (Choose three.)
A. All machines have to rejoin the new domain.
B. The profiles of the users remain unchanged.
C. Samba configures its internal NTP server to synchronize the systems clocks of all domain members.
D. The user accounts and machine accounts are migrated into the new database.
E. A basic set of DNS records required for AD operation are provisioned.