Willow Corp. uses a perpetual inventory system. Which of the following statements about taking a physical count of inventory is true?

A$.$ Willow must take a physical count of inventory to check the accuracy of the perpetual inventory records.

B$.$ It is not necessary for Willow to take a physical count of inventory.

C$.$ Willow must take a physical count of inventory in order to determine cost of goods sold for the accounting period.

D$.$ Willow must take a physical count of inventory in order to perform inventory ratio analysis.