For each of the following situations, indicate which inventory cost formula would be the most appropriate to use.

$($a$)$ KK Kars is a small automobile dealership. Each car it sells has a unique serial

number, and the cars are not interchangeable.

$($b$)$ Easyway Grocery store carries milk as one of its main inventory items. Each

$4-$litre jug of milk carries an expiry date. When new milk arrives from the

supplier, Easyway puts the new milk in the back of the refrigerator, leaving

the older milk at the front.

$($c$)$ Kong Koal is a company that sells bulk coal. When Kong purchases the coal

from the supplier, the new coal is poured onto a large pile. When customers

purchase the coal, it's the newest coal they are buying $($the older coal being

buried whenever new coal is added$).$