Jack (69) and Kendra (67) are married and will file a joint return. During the year, Jack received $9,000 in social security benefits, and Kendra received $28,000 in benefits. In addition, the couple earned $2,000 in interest income, and Jack, a retired military officer, received pension benefits totaling $73,000. How much, if any, of the couple's social security benefits are taxable? 100%. 85%. 50%. None of their benefits are taxable.