Which of the methods in $($b$)$ above does the following? $(1)$ Provides the most conservative estimate of ending inventory. Excluding Both Markups and Markdowns. $(2)$ Provides an approximation of lower$-$of$-$cost$-$or$-$market. Excluding Markdowns but Including Markups $(3)$ Is used in the conventional retail method. Including Both Markdowns and Markups