The Nelson Company's radio division currently is purchasing transistors from the Charlotte Co. for $3.50 each. The total number of transistors needed is 8,000 per month. Nelson Company's electronics division can produce the transistors for a cost of $4.00 each and they have plenty of capacity to manufacture the units. The $4 is made up of $3.25 in variable costs, and $0.75 in allocated fixed costs. What should be the range of a possible transfer price?