Section 1231 property is really confusing me. Could any of the following be classified as section 1231? stock, inventory, accounts receivable, or a

Section 1231 property is really confusing me. Could any of the following be classified as section 1231? stock, inventory, accounts receivable, or a computer? I want to say a computer because it can be long term depreciable property, but I think it may be section 1245. Please help me make sense of this.