On August 31, Year 10, Harvey Co. decided to change from the FIFO periodic inventory system to the weighted average periodic inventory system. Harvey uses U.S. GAAP, is on a calendar year basis, and does not present comparative financial statements. The cumulative effect of the change is determined: A. As of January 1, Year 10. During the eight months ending August 31, Year 10, by a weighted average of the purchases. During Year 1 by a weighted average of the purchases. As of August 31, Year. B. C. D