The Ewing Company showed common stock of $200,000, preferred stock of $10,000 and retained earnings of $100,000 on its December 31, 2017 balance sheet. During 2018, Ewing earned net income of $150,000 and declared and paid $30,000 in dividends. What was Ewing's retained earnings balance at December 31, 2018? a. $430,000 O b. $220,000 O c. $120,000 O d. $250,000