Horizon company has $25 per unit selling price, $8.00 per unit in variable production cost and $1.00 per unit in variable selling and administrative cost. The annual fixed production cost is $400,000. The annual fixed selling and administrative cost is $50,000. Required: a. Complete the table below for each year. Assume a FIFO flow. 2017 2018 2019 2020 Units Produced 120,000 150,000 100,000 100,000 Units Sold 110,000 120.000 140,000 100,000 Manufacturing cost per unit (using full costing) Operating income under variable costing Operating income under full costing Ending inventory using variable costing ($) Ending inventory using full costing ($) b. Explain how and why your results in requirement a above differed with respect to operating income between variable costing and full costing