21. To qualify for like-kind exchange treatment under, which of the following requirements must be satisfied? a. The form of the transaction is a sale or exchange. b. Both the property transferred and the property received are held either for productive use in a trade or business for investment. C. The exchange must be completed by the end of the second tax year following the tax year in which the taxpayer relinquishes his or her like-kind property. d. Only choices a. and b. e. Choices a., b., and c