I have a case structure

Case Type A

  Child Case A1

  Child Case A2

  Child Case A3

Among below ,what are the statements are true.

1. To resolve Case A, A1 case also should be resolved

2. Child Case A2 can be instantiated without Case A

3. A1,A2,A3 must be instantiated for Case A to process correclty

4.Class of A1 case type must inherit from Case of A case type

I hope, 2 is correct