I don't understand how is the answer is number 2, how it is calculated?

An entity pays $100,000 rent of factory which has a maximum capacity to produce 50,000 units if operated continuously withoutshut down. However, allowing for routine maintenance and outages, the capacity is expected to be not more than 40,000 units. Forthe year 20X5, entity has budgeted to produce 25,000 units considering fall in demand. However, it could only produce 20,000 unitsduring 20X5.

The allocation of rent for each unit produced in year 20X5 will be:

1.$ 2 per unit produced

2.$ 2.5 per unit produced

3.$ 4 per unit produced

$ 5 per unit produced