Which of the following statements concerning budget preparation for a merchandiser is correct? A. Only an understanding of cost behavior is required to prepare an operating expense budget. B. Assuming only a portion of a company's sales are made on account, bad debt expense under the income statement method is calculated by multiplying sales on account by the estimated uncollectible percentage. C. If a company requires its ending inventory to equal a certain percentage of the cost of next month's sales, the company would be able to prepare purchases budgets for 4 months if it only knew the cost of sales for those 4 months. D. Operating expenses differ from operating cash outflows solely as a result of timing differences between when an expense is incurred and when an expense is paid. E. None of the above statements are correct