I am playing in a new band and they like to write songs that go E-C-D....or sometimes D-Bb-C, etc. 3 chords, all a whole step apart, but starting with that first chord. I tried playing E and D scales respectively (both major, minor and minor pentatonic), figuring that was the key it was in, but don't see that 2nd chord anywhere in the scale. What scale would work for this progression?? There is a change in the chorus, but basically the same chords, just a different progression. thanks.