Last week’s prime-time special, introducing viewers to the casting and rehearsal process in bringing this Rodgers and Hammerstein classic to television, did a great job of promotion, stressing the point of just how high-risk, and exciting, a live TV premiere is bound to be. And here it comes. At one point in TV’s history, everything was presented this way – but tonight, a live musical, starring Carrie Underwood and featuring Audra McDonald and Laura Benanti, is an absolute rarity. Be watching, and be recording. In last week’s rehearsal footage, Underwood looked just perfect in the role.