Company: AT&T Inc.

AT&T Inc. released its financials for the fiscal year ending December 31, 2023. The company reported total revenue of $120 billion, with a cost of goods sold (COGS) of $60 billion and operating expenses of $40 billion. Net income stood at $20 billion. From this data: a) Calculate the gross profit margin. b) Determine the operating profit margin. c) Compute the net profit margin. d) Evaluate the return on assets (ROA) if the company's total assets amount to $300 billion.