Which of the following statements is correct? a. depreciation reduces a firm's cash balance, so an increase in depreciation would normally lead to a reduction in the firm's net cash flow. b. people sometimes talk about the firm's net cash flow, which is shown as the lowest entry on the income statement, hence it is often called "the bottom line." c. depreciation and amortization are not cash charges, so neither of them has an effect on a firm's reported profits. d. net cash flow (ncf) is often defined as follows: net cash flow = net income + depreciation and amortization charges. e. the more depreciation a firm reports, the higher its tax bill, other things held constant.