Question 2 (18 marks) a) What role does the Black Box play in the business modelling process? Illustrate with a suitable diagram (5 marks) b) Are Inuence Diagrams indispensable in the Modelling process? (5 marks) 0) Consider the following spreadsheet: ITEMS Notation: Sales Selling Price each TOTAL REVENUE Expenses: Advertising Bad Debt Insurance Maintenance Salaries TOTAL EXPENSES Income before Tax Tax Payable Income after Tax Construct a Black Box and Influence Diagram representing the above. (8 marks)