What are the relevant use cases for helper key figures? Note: There are 2 correct answers to this questions.

What are the relevant use cases for helper key figures? Note: There are 2 correct answers to this questions.
A . Used at any level of calculation level except the Request Level
B. Used when you have more than three inputs at different planning levels in one calculation
C. Used by end-users in planning views to help visualize cross-period calculations
D. Used to break down a large calculation into manageable subcalculations

Answer: B,D