When Calculating a Firm's Free Cash Flow from Earnings Before

When calculating a firm's free cash flow from earnings before interest and taxes we must add back depreciation,amortization and depletion expense and allowances because

A) they are non-cash expenditures.
B) the accounting method for reporting such expenses may be different from that reported to the taxing authority.
C) they approximate the value of fixed asset purchases during the year.
D) they are unrelated to the amount of taxes paid during the year.