Dollar$-$Value LIFO

When the double$-$extension approach to the dollar$-$value LIFO inventory cost flow method is used, the inventory layer added in the current year is multiplied by an index number. How would the following be used in the calculation of this index number?

a$.$

$$Ending Inventory

at Current$-$Year CostEnding Inventory

at Base$-$Year CostNot UsedDenominator

b$.$

$$Ending Inventory

at Current$-$Year CostEnding Inventory

at Base$-$Year CostNumeratorDenominator

c$.$

$$Ending Inventory

at Current$-$Year CostEnding Inventory

at Base$-$Year CostDenominatorNumerator

d$.$

$$Ending Inventory

at Current$-$Year CostEnding Inventory

at Base$-$Year CostNumeratorNot Used