A. You must delete members one by one.

B. You must delete a reference to a member from all data forms before deleting it from the dimension.

C. In a data form definition, you selected @IDescendants(IT) for the entity dimension in the page section.
The IT member will remain but 2 of its 10 cost centers are being removed. You must remove the reference to "IT" in this data form.

D. You should back up all data for the deleted entity members; after a member is deleted, the data is not retained.

E. A database refresh is required after deleting members from the Entity dimension.