80. Sophia is a self-employed accountant. John is a house painter. Both Sophia and John are members of a barter club. They agreed to exchange their services for payment. Sophia did the bookkeeping for John and John painted Sophia's house. Sophia usually charges $500 for the bookkeeping and John usually charges $600 for painting the house. During the year, Sophia had a cash income of $28,000, credit card income of $35,500. What amount are Sophia's gross receipts? a) $64,100 b) $63,500 C) $64,000 d) $36, 100