What is the operating income for the year ended December 31, 20X3 if a firm has the following income statement account year end balances at December 31, 20X3: net sales of $100,000; cost of goods sold of $30,000; selling expenses of $20,000; general expenses of $10,000; administrative expenses of $15,000; interest expense of $5,000? 20X3

a. $20,000

b. $25,000

c. $50,000

d. $70,000