A corporation is a calendar-year taxpayer. On January 21, 20x7, all of A's stock was acquired by J Corporation. J's tax year ends January 31, 20x7. J is the common parent corporation of a six-corporation affiliated group that has filed a consolidated tax return for a number of years. Which of the following is true?

A. A Corporation may elect to file a consolidated return for the period of January 1, 20x7 through December 31, 20x7.

B. A corporation may elect to keep its tax year for one additional period and file a separate return for the period of January 1, 20x7 through December 31, 20x7

C. A corporation must file a consolidated return for the entire period, January 1, 20x7, through December 31, 20x7.

D. A corporation must file a consolidated return with J for the period January 22-January 31 and a separate return for the period January 1-Janaury 21, 20x7.