Ana wants to paint her dogs doghouse. She has 4 colors: Green, Maroon, Blue and Wheat. One color will cover the walls, and another color will be used for the trim. (For example, green walls with wheat trim = GW.) Which one of these answers show all of the possible color combinations?

A. BW, BM, BG, BB, MW, MB, MG, MM, GW, GB, GM, GG
B. GM, GB, GW, MG, MB, MW, BG, BM, BW, WG, WM, WB
C. MM, MG, WB, WM, WG, BB, BG, BM, WB, GB, GM, GW