Please show all work for calculations. Thanks you

Consider the following data for the airline industry for December 2015 (EV = enterprise value, Book = equity book value). Discuss the potential challenges of using multiples to value an airline. All the multiples show a great deal of variation, suggesting the following: (Select the best choice below.) A. Profitability and growth vanes widely across firms. B. Smaller airlines are more efficient than their larger competitors. C. Ratios were probably computed at different points in time. D. Airlines are very diversified nowadays. Which of these ratios is probably the most useful? A. EV/Sales B. EV/EBITDA C. P/E D. P/Book