Band with a classic line-up of Messrs Daltrey, Townshend, Entwistle and Moon (3,3)
I believe the answer is:
the who
(Other definitions for the who that I've seen before include "Pop group (Tommy, Quadrophenia)" , "questionable identity?" , "Tommy, Quadrophenia rock group" , "60s rock group" , "British pop group" .)