O'Brien Company manufactures and sells one product. The following information pertains to each of the company's first three years of operations:qquad$$4$Variable selling and administrative. qquad$$3$Fixed costs per year:Fixed manufacturing overhead. qquad $$660,000$Fixed selling and administrative expenses....$$120,000$

During its first year of operations, O'Brien produced $100,000$ units and sold $80,000$ units. During its second year of operations, it produced $75,000$ units and sold $90,000$ units. In its third year, O'Brien produced $80,000$ units and sold $75,000$ units. The selling price of the company's product is $$75$ per unil.

Required:

Assume the company uses variable costing and a FIFO inventory flow assumption $($FIFO means first$-$in first$-$out. In other words, it assumes that the oldest units in inventory are sold first$)$:

a$.$ Compute the unit product cost for Year $1,$ Year $2,$ and Year $3.$

b$.$ Prepare an income statement for Year $1,$ Year $2,$ and Year $3.$