QUESTION 2 a) Conceptual design is the first stage in the database design process. The output of this process is a conceptual data model that describes the main entities, attributes, relationships, and constraints of a given problem domain. Discuss FOUR (4) steps with their activities in conceptual design phase. (8 marks) b) Mobile Database is a database that resides on a mobile device such as smart phone and notebook. Describe FOUR (4) challenges in Mobile Database. Give an example for each challenge. (8 marks) c) Explain TWO (2) advantages of database system approach over file-based approach. (4 marks)