When do you recommend using an external hierarchy? Note: There are 3 correct answers to this question.

When do you recommend using an external hierarchy? Note: There are 3 correct answers to this question.
A . The hierarchical structure will be time-dependent.
B . The structure will contain formulas.
C . The structure will depend on the order of the row characteristics.
D . The structure exists in the source system.
E . The query data will be restricted to a hierarchy node.

Answer: A,D,E