Heiden Inc. accounts for inventory using the LIFO inventory method. Beginning inventory on January $1$ consists of $18,000$ units at a cost of $$5$ per unit. During the year, the company sold more items than purchased, causing the ending inventory balance on December $31$ to drop to $13,500$ units. Assuming a tax rate of $25\%$ and a current replacement cost of inventory of $$8$ per unit, what is the LIFO liquidation effect on $($a$)$ pretax and $($b$)$ after$-$tax income?

a$.$LIFO liquidation effect on pretax income

b$.$LIFO liquidation effect on after$-$tax income