Chameleons are lizards that can change colour. In one particular colony the chameleons are either red, blue or green. When two chameleons of different colours meet they get a bit stressed out, and they both change to the other colour to calm themselves down.
For example if a red chameleon and a blue chameleon meet, they both change to green.
Chameleons in this colony never change colour other than for this reason.
If there are currently 10 red, 12 blue and 15 green chameleons, is it possible that all the chameleons end up:
a) red?
b) blue?
c) green?