the full question is . You can continue to use your old tractor at a cost of $13,000 annually for the next five years. Alternatively, you can purchase a newer tractor for $22,000 plus $5,000 annual maintenance for the next five years. At a cost of capital of 15 percent, you should: a. Buy the newer tractor and save $568 in equivalent annual costs. b. Buy the new tractor and save $1437 in equivalent annual costs. c. Keep the old tractor and save $588 in equivalent annual costs. d. Keep the old tractor and save $1437 in equivalent annual costs. e. You are indifferent between the two options