4. Jones Company changed its method of depreciation from the accelerated depreciation method to the straight-line method. Generally accepted accounting principles require that this accounting principle change must be reported by

a.	restating past financial statements to retroactively present the new accounting principle
b.	disclosing the justification for the accounting principle change and treating the accounting principle change prospectively
c.	presenting the cumulative effect of the change in the current year's income statement and presenting pro forma effects on prior periods presented
d.	simply justifying the change to the new accounting principle