Where is the LDAP administrator account defined ?

After analyzing a slapd.conf file, an administrator noted that the rootdn and rootpw directives are not present.
Where is the LDAP administrator account defined ?

A.
It is using the default account admin with the password admin

B.
The account is defined by an ACL in slapd.conf

C.
It is using the default account admin with a null password

D.
The account is defined in the file /etc/ldap.secret

E.
The account is defined in the file /etc/ldap.root.conf