Karen, an accrual basis taxpayer, sold goods in December 2019 for $20,000. The customer was unable to pay cash. So the customer gave Karen a note for $20,000 that was payable in April 2020. The note bore interest at the Federal rate. The fair market value of the note at the end of 2019 was $18,000. Karen collected $20,500 from the customer in April 2020, $20,000 principal plus $500 interest. Under the accrual method, Karen must recognize income of: