Determine the taxable amount of Social Security benefits for the following situations. If required, round your answers to the nearest dollar. If an amount is zero, enter "O". a. Erwin and Eleanor are married and file a joint tax return. They have adjusted gross income of $38,400, no tax-exempt interest, and $13,440 of Social Security benefits. As a result, s 7,550 X of the Social Security benefits are taxable. b. Assume Erwin and Eleanor have adjusted gross income of $16,600, no tax-exempt interest, and $18,260 of Social Security benefits. As a result o of the Social Security benefits are taxable. c. Assume Erwin and Eleanor have adjusted gross income of $86,500, no tax-exempt interest, and $12,975 of Social Security benefits. As a result, of the Social Security benefits are taxable. Feedback Check My Work If a taxpayer's income exceeds a specified base amount as much as 85 percent of Social Security retirement benefits must be include gross income. The taxable amount of benefits is determined through the application of one of two formulas that utilize a unique measu Income-modified adjusted gross income (MAGI)