Suppose a nation has a tax rate of 10% on the first $10,000 of taxable income, then 15% on the next $20,000, then 20% on the next $30,000, and 30% on all taxable income above $60,000. There is a $4,000 exemption per family member. Anand's family has eight members and earns $80,000 per year. What is his family's average tax rate? O a. 15.5% O b. 9.5% O c. 30% O d. 20%