NEW YORK (AP) – ABC’s “Good Morning America” is celebrating its 40th anniversary Thursday with a crowded studio filled with all the men and women who hosted the day-opening broadcast through its history. Starting with original hosts David Hartman and Nancy Dussault, producers cleverly moved through the hosts chronologically as they raised coffee mugs and looked at the camera with the show’s signature greeting, “Good Morning, America.” For many years the No. 2 morning show behind NBC’s “Today,” the ABC show has been on top the past few years with current hosts George Stephanopoulos and Robin Roberts. The hosts reminisced, with Charles Gibson recalling how he felt going to work on Sept. 12, 2001, following the terrorist attacks, knowing that it would be the most important broadcast of his career.