Required: Carl and Karina file a joint return. Karina earned a salary of $42,500 and received dividends of $3,360, taxable interest income of $2,180, and nontaxable interest of $1,090. Carl received $9,720 of social security benefits and a gift of $6,180 from his brother. What amount of social security benefits is taxable to Carl and Karina? Taxable social security benefits