The country "Macquarica" has a tax rate of 5% on the first $20,000 of a family's taxable income, then 20% on the next $30,000, then 50% on all taxable income above $50,000 and provides a $5,000 tax exemption per family member. Bob's family has five members and the family earns $100,000 per year. Calculate the family's average tax rate. a. 75% b. 37.5% c. 50% d. None is correct e. 19.5%