In anticipation of a busy holiday season, management expects to be able to sell all of the stylus units that they can produce, which at current capacity is $50,000$ units. What will operating income be in December if $50,000$ units are produced and sold using $($a$)$ variable costing, and $($b$)$ absorption costing? Assume no change to selling price, unit costs, or fixed costs in December.

$a$