Which of the following is the most commonly used implementation of a hierarchical database?
A.
Directory Access Protocol
B.
XWindows
C.
UNIX
D.
Lightweight Directory Access Protocol
Explanation:
The most commonly used implementation of the hierarchical model is in the Lightweight Directory Access Protocol (LDAP) model. You can find this model alsoused in the Windows registry structure and different file systems, but it is not commonly used in newer database products.