Liberty Limited reports its financial results in accordance with IFRS. Liberty used the weighted-average cost method to value its inventories in 20X4 but switched to the first-in-first-out method in 20x5, as FIFO was used by its competitors. Assuming that all amounts are material, what type of accounting change is this? O a. Correction of an error from prior period O b. Change in accounting policy Oc. Change in accounting estimate