An administrator is configuring LDAP for Cisco UCM with Active Directory integration. A customer has requested to use `ipphone` instead of `telephoneNumber' as ...

An administrator is configuring LDAP for Cisco UCM with Active Directory integration. A customer has requested to use `ipphone` instead of `telephoneNumber' as the phone number attribute. Where does the administrator specify this attribute mapping in Cisco UCM?

A. LDAP Custom Filter B. LDAP Authentication C. LDAP Directory user fields D. LDAP Directory custom user fields