Problem 4-54 (LO. 4, 5) Linda and Don are married and file a joint return. In 2022, they received $12,000 in Social Security benefits and $35,000 in taxable pension benefits and interest. The applicable higher/lower bases for Social Security computations for married filing jointly are $32,000 and $44,000. a. Compute the couple's adjusted gross income on a joint return. 39,500 b. Don would like to know whether they should sell for $100,000 (at no gain or loss) a corporate bond that pays 8% in interest each year and use the proceeds to buy a $100,000 nontaxable State of Virginia bond that will pay $6,000 in interest each year. Assume that their marginal tax rate is 12%. Although the interest received on the state bond is taxable it still is included in modified adjusted gross income, impacting the taxability of their Social Security benefits. Their AGI would be $ c. In the preceding situation part (a), if Linda works part-time and earns $30,000, by how much would Linda and Don's adjusted gross income increase?