Who composed the tune most closely associated to the "Infernal Galop" as part of the "Orpheus in the Underworld" opera?
Can-can:  The "Infernal Galop" from Jacques Offenbach's "Orpheus in the Underworld" is the tune most associated with the can-can. Orpheus in the Underworld:  Its score was composed by Jacques Offenbach to a French text written by Ludovic Halévy and later revised by Hector-Jonathan Crémieux.
Jacques Offenbach