Which of the following statements is true? Oa. The breakdown of tax expense between current and deferred may provide useful information regarding the comparison of tax burdens between companies. Ob. One-time effects within a company's effective tax rate should be removed before comparing the effective tax rates across companies (or across years for the same company). Oc. An analysis of earnings before interest, taxes depreciation, and amortization (EBITDA) is often a better approach to comparing the operating results of two companies. Od. All these observations are correct