The optimal level of inventory is affected by all of the following except the?

d. current level of inventory

answer : 

D  :  current level of  inventory

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D. The current level of inventory does not affect the optimal level of inventory.

correct answer is D

 current level of inventory

the optimal  answer d current level of inventory 

The Economic Order Quantity suggest that order cost, usage rate and unit cost are essential when determining Optimal inventory level. 

The correct answer is D

option D is correct according to my knowledge 

its A)usage rate of inventory per period>>>>>>>>>>>>>>>>>>>>>>>>

a. usage rate of inventory per period