A manufacturing company incurs rent costs of $12,500 per month. The company manufactured 250,000 units in May and 300,000 units in June. The cost per unit in May and June, respectively, is:

a) $0.04 and $0.05
b) $0.05 and $0.04
c) $20.00 and $24.00
d) $24.00 and $20.00