Sunny Ltd produces four products. Information on each product is shown below: A B C D Budgeted sales (units) 4,000 2,000 3,000 1,000 Selling prices $60 $45 $52 $95 Production costs per unit Direct materials $27 $10 $18 $40 Direct labour $12 $16 $16 $24 Variable overhead $3 $4 $4 $6 The company is experiencing shortage of skilled labour time needed for production of all the four products. Presently, only 16.600 hours of skilled labour time are available each week and the wages paid for each direct labour hour is $8. Required: (a) Perform relevant analysis of the limiting factor (16,600 labour hours), determine how many units of each product to be produced and sold in order to maximise the total contribution margin. (14 marks) (b) Managers often use the relevant costs concept for making business decisions. Distinguish between relevant and irrelevant costs and provide two examples for each type of costs. (6 marks)