Sonya used to earn $25,000 a year selling real estate, but she now sells greeting cards. The return to entrepreneurship in the greeting cards industry is $14,000 a year. Over the year, Sonya bought $10,000 worth of cards from manufacturers and sold them for $58,000. Sonya rents a shop for $5,000 a year and spends $1,000 on utilities and office expenses. Sonya owns a cash register, which she bought for $2,000 with funds from her savings account. Her bank pays 3 percent a year on savings accounts. At the end of the year, Sonya was offered $1,600 for her cash register. find out Sonya's explicit costs, implicit costs, and economic profit.