Many consider the Arthur Laurents-Jule Styne-Stephen Sondheim musical “Gypsy” one of the greatest ever written. In the new revival on Broadway, six-time Tony Award-winner Audra McDonald takes on one of musical theater’s most demanding roles: Rose, who pushes her daughters onto the stage. Correspondent Mo Rocca talks with McDonald, director George C. Wolfe, and theater expert Erick Neher about Rose, and whether she should be viewed as a monster or a sympathetic character.