Which of the following transactions or events generates a Section 1231 gain or loss? Assume all assets are held for more than one year. For each option, explain your answer.
a. Theft of an uninsured diamond engagement ring, with $8,000 basis and a $15,000 FMV.
b. Gain due to condemnation of land used in a business.
c. Loss on sale of a warehouse.
d. Gain of $4,000 on the sale of equipment. Depreciation deductions allowed were $10,000.