Suppose the tax rate on the first $10,000 income is 0 percent; 10 percent on the next $20,000; 20 percent on the next $20,000; 30 percent on the next $30,000, and 40 percent on any income over $80,000. Family X has income of $50,000 What is the marginal and average tax rate for Family X? O A. marginal-20 percent, average-12 percent B. marginal-10 percent, average-12 percent O C. marginal-25 percent; average-15 percent D. marginal-15 percent, average-25 percent