Which of the dates in group B could be moved into group A, and why?
Group A
January 12th, 2012
April 3rd, 2012
June 2nd, 2012
December 1st, 2012
March 4th, 2012
Group B
August 10th, 2012
October 3rd, 2012
January 14th, 2012
February 6th, 2012
September 9th, 2012