Which of the following tasks can you perform using SAP cloud Application Cloud Application Studio only?

Extensions to cloud solution from SAP can be performed using either the adaption tools or SAP cloud Application Studio.

Which of the following tasks can you perform using SAP cloud Application Cloud Application Studio only? NOTE: There are 3 correct answers to this question.
A . Add, modify, delete, or hide extension fields.
B. Extend the business logic of the cloud solution standard object.
C. Build new business logic for the cloud solution.
D. Build custom business objects and corresponding user interfaces.

Answer: B,D