The griffins and the corbins live in the same city and pay the same sales tax rate, and both families made $12,000 in taxable purchases last year. if the griffins made $73,000 and the corbins made $29,000 last year, is the sales tax in their city an example of a regressive tax? a. yes, because the corbins paid a higher percentage of their income in sales tax than the griffins did. b. no, because the corbins paid a higher percentage of their income in sales tax than the griffins did. c. no, because the griffins and the corbins both paid the same sales tax rate. d. yes, because the griffins and the corbins both paid the same sales tax rate.