Choice "C" is correct. Capital assets include all marketable securities unless the taxpayer is a dealer.Choice "a" is incorrect. Accounts receivable of a business are excluded from the definition of capital assets.Choice "d" is incorrect. All depreciable assets of a business are excluded from the definition of capital assets. They are defined as Section 1231 assets.Choice "b" is incorrect. Inventory of a business is excluded from the definition of capital assets.