<xs:element name="ParentDomain" nillable="true" type="xs:string" />
The crossRef!systemFlags attribute's FLAG_CR_NTDS_NC and FLAG_CR_NTDS_DOMAIN bits are set to 1 and the client has access rights to read the attribute. See [MS-ADTS] section 126.96.36.199.1.1.
The crossRef!dnsRoot attribute is present and the client has access rights to read the attribute.
The crossRef!Enabled attribute is not present, is not equal to FALSE, or cannot be read due to the client lacking access rights to read the attribute.
If no crossRef objects satisfy the above requirements, the server returns a null ActiveDirectoryDomain/ParentDomain element. If multiple crossRef objects satisfy the above requirements, then only one of the crossRef object MUST be chosen, but any of the objects MAY be chosen<37> in constructing the response. If the crossRef!dnsRoot attribute on the chosen crossRef object satisfying the above requirements has multiple values, then only one of the values MUST be chosen, but any of the values MAY be chosen<38> to populate the element.