Which of the Following Costs Is a Relevant Inventory Stockout

Which of the following costs is a relevant inventory stockout cost?

A) The costs of obsolescence and costs of insurance that change with the quantity of inventory held.
B) The return forgone by investing capital in inventory rather than elsewhere.
C) The lost contribution margin on sales forgone as a result of customer dissatisfaction due to unavailability of goods.
D) The costs of storage space owned that cannot be used for other profitable purposes when inventories decrease.