Sparn Limited incurs the following costs to produce and sell a single product: Variable costs per unit: Direct materials$$23$ Direct labour $11$ Variable manufacturing overhead $4$ Variable selling and administrative expenses $6$ Fixed costs per year: Fixed manufacturing overhead $324,000$ Fixed selling and administrative expenses $504,000$ During the last year, $54,000$ units were produced and $46,500$ units were sold. The Finished Goods Inventory account at the end of the year shows a balance of $$285,000$ for the $7,500$ unsold units. Required:$1-$a$.$ Is the company using absorption costing or variable costing to cost units in the Finished Goods Inventory account? multiple choice $1$Absorption costingVariable costing $1-$b$.$ Show computations to support your answer.