Regarding AD server and LDAP server, which of the following descriptions is wrong?

Regarding AD server and LDAP server, which of the following descriptions is wrong?
A . AD is a dedicated directory server for Windows Server
B . LDAP can be installed on Windows Server
C . The directory service protocol used by the AD server is the AD protocol
D . The directory service protocol used by the AD server is the LDAP protocol

Answer: C