Which of the following would be considered restrictions of a hierarchical database structure?

i.To be able to access a certain data entity within a hierarchical database requires the knowledge of which branch to start with and which route to take through each layer until the data are reached.
ii. To be able to access a certain key entity within a hierarchical database requires the knowledge of which branch to start with and which route to take through each layer until the data are reached.
iii. It does not use indexes as relational databases do for searching procedures.
iv. It does use indexes as relational databases do for searching procedures

A.
i, iii

B.
i, ii, iii

C.
ii, iii, iv

D.
i, ii

Explanation:
The hierarchical structured database is one of the first types ofdatabase model created, but is not as common as relational databases. To be able to access a certain data entity within a hierarchical database requires the knowledgeof which branch to start with and which route to take through each layer until thedata are reached. It does not use indexes as relational databases do for searching procedures. Also links (relationships) cannot be created between different branches and leaves on different layers.