Tomoka Company sold some machinery to River Company on January 1, 20X1. The cash selling price would have been $284,310. River entered into an installment sales contract which required annual payments of $75,000, including interest at 10%, over five years. The first payment was due on December 31, 20X1. What amount of interest income should be included in Tomoka's 20X2 income statement, the second year of the contract? (a) 7,500. (b) $23,774. (c) $15,000. (d) $20,931