Bread B and C would have no mould grown on it. Mould requires a warm and moist environment to grow in. Bread B was toasted before, hence all the moisture would be removed and thus unsuitable for mould to grow. Bread C is placed in the fridge where moisture would be at its minimal, its also a cold environment, hence mould would not grow. Bread A has water sprinkled on it and being in room temperature would encourage mould to grow.