Doesn't necessarily have to be your bias, just someone that you respect the talents of.
For me, I really enjoy Eunji's range and color. Her voice has such a bright sound to it, and it's even noticeable above her groupmates in their songs.
As far as pure color goes, I think Choa has her beat. She has a softer, warmer color and when she smiles while singing it really shines through.
