Rose earns $100,000 a year, and Jack earns $50,000 a year. They each buy the same model of television and pay $200 in sales tax. Mia's income tax rate increased when she got a promotion and a raise. Mr. Brown and Mr. Joseph earn different annual incomes; however, they both pay income tax equivalent to 15% of their income.
a. Proportional tax
b. Regressive tax
c. Progressive tax
d. Insufficient information