Label the following look-back periods for 20XC by months. A B C D 20XA 20XB Included in Look- Diagram Label Months Covered by Diagram Label Back Period for 20XC? ABCD January 1-June 30, 20XA Yes July 1-December 31, 20XA Yes January 1-June 30, 20XB No D July 1-December 31, 20XB No