Imani, an accrual basis taxpayer, sold goods in December $2023$ for $$20,000.$ The customer was unable to pay cash. So the customer gave Imani a note for $$20,000$ that was payable in April $2024.$ The note bore interest at the Federal rate. The fair market value of the note at the end of $2023$ was $$18,000.$ Imani collected $$20,500$ from the customer in April $2024,$ $$20,000$ principal plus $$500$ interest. Under the accrual method, Imani must recognize gross income of:

a$.$ $$20,500$ in $2024.$

b$.$ $$20,500$ in $2023.$

c$.$ $$18,000$ in $2023$ and $$2,500$ in $2024.$

d$.$ $$20,000$ in $2023$ and $$500$ in $2024.$