Sonic Lid currently design and manufacture their own range of digital radios. The cost details for their latest range are as follows: Direct Materials $900,000 Direct Labour $400,000 Variable Overhead $300,000 Fixed Overhead $500,000 Total Manufacturing Cost $2, 100,000 Quantity Produced 7,000 units Cost Per Unit $300 An overseas manufacturer has offered to supply a similar range of digital radios for $250 per unit. REQUIRED [a] Should Sonic Lid make or buy their range of digital radios? Show all calculations. [b] What other factors should be taken into consideration