DEF Ltd. had the following information for the year 2023:

 - Beginning Inventory: $50,000

 - Purchases: $200,000

 - Ending Inventory: $40,000

 Calculate:

 a) Cost of Goods Sold (COGS).

 b) Inventory Turnover Ratio.

 c) Days Sales Outstanding (DSO) if the accounts receivable at the beginning of the year were $30,000 and at the end of the year were $40,000.