Sandra sold a plot of land to Roberto on June $30,2022.$ The sales price was $$50,000,$ and Sandra's basis in the property was $$30,000.$ Roberto made one payment of $$10,000$ during $2023$ and agreed to pay an additional $$10,000$ each year, plus interest, for the next four years. Using the installment method, what is Sandra's taxable gain for $2023?$

$$4,000$

$$10,000$

$$20,000$

$$50,000$