Answer: D. Specific identification
Explanation: The specific identification method of inventory taking is probably the most time consuming. This is because it is based on principles which are: being able to track each item in an inventory; being able to track the cost of each item individually; being able to relieve inventory for the specific cost associated with an inventory item when it is sold. It is quite clear then that despite its high degree of accuracy to the cost of inventory, it is very time-consuming as it tracks inventory items on individual unit basis restricting its use to smaller inventory volumes and smaller firms.